Psychosexual Disorders

Psychosexual disorders are a group of conditions in which psychological factors lead to disturbances in sexual desire, arousal, performance, or gender identity.

2. Epidemiology

3. Anatomy and Physiology of the Normal Sexual Response

This is the foundational model for understanding sexual dysfunctions — each dysfunction maps onto a disruption of one or more phases ^[2]:

Phase	What Happens	Physiology	Key Points
Phase 1: Desire	Sexual fantasies and desire to have sexual activity	Central (hypothalamic–limbic), modulated by testosterone, dopamine; inhibited by serotonin, prolactin	This is the "wanting" phase — purely psychological/neurochemical. Disrupted in hypoactive sexual desire disorder
Phase 2: Excitement	Subjective sense of sexual pleasure + accompanying physiological changes: erection in males, vaginal lubrication in females	Parasympathetic activation → NO release → vasodilation → engorgement. Vaginal transudation in females	Duration varies. Disrupted in erectile disorder, female sexual interest/arousal disorder
Phase 3: Orgasm	Peaking of sexual pleasure with release of tension + rhythmic contraction of perineal muscles and pelvic reproductive organs	Sympathetic + somatic: M — sensation of ejaculatory inevitability → ejaculation; F — contraction of outer 1/3 of vagina	Disrupted in premature ejaculation, delayed ejaculation, female orgasmic disorder
Phase 4: Resolution	Muscle relaxation, general well-being	Parasympathetic rebound, oxytocin/prolactin release	Refractory period: men are refractory to further erection and orgasm, but NOT women (women can have multiple orgasms without a refractory period) ^[2]

High Yield — Male vs Female Response Curves

The classic sexual response graph shows:

Males: relatively stereotyped single peak → orgasm → distinct refractory period → resolution
Females: more variable — can have multiple orgasms (no refractory period), or a plateau phase without reaching orgasm, or a gradual return to excitement without distinct refractory period ^[2]

4. Aetiology and Pathophysiology

4.1 Aetiology of Sexual Dysfunctions

Sexual dysfunctions are almost always multifactorial — a biopsychosocial model is essential ^[2]:

"May date back to a period of abstinence from debilitation" ^[2] — i.e., an initial organic cause (e.g., post-MI, post-surgery) leads to a period of sexual inactivity, which then breeds performance anxiety and perpetuates the dysfunction even after the organic cause resolves.

Diabetes mellitus — direct effect on sexual performance via:
- Vasculopathy: microvascular disease → impaired penile blood flow → erectile dysfunction
- Autonomic neuropathy: damages parasympathetic nerves (S2–S4) → impaired NO-mediated vasodilation → erectile dysfunction; also impairs vaginal lubrication in females
- DM is the single most important medical cause of ED — up to 50% of diabetic men develop ED ^[2]

Drugs (extremely high yield — always ask about medications!) ^[2]:

Drug Class	Examples	Mechanism of Sexual Dysfunction
Antihypertensives	Beta-blockers, CCBs, spironolactone	BB: ↓sympathetic drive → ↓arousal, ejaculatory difficulty; Spironolactone: anti-androgen effect → ↓libido, gynaecomastia, ED
Antidepressants	SSRIs, TCAs, MAOIs	SSRIs: ↑serotonin → inhibits dopamine and NO pathways → delayed orgasm, ↓libido (most common cause of medication-induced SD); TCAs: anticholinergic → ↓arousal; MAOIs: multiple mechanisms
Mood stabilisers	Lithium	Mechanism unclear; may affect thyroid function (hypothyroidism → ↓libido)
Anxiolytics	Benzodiazepines	CNS depression → ↓arousal, ↓desire
Antipsychotics	FGA and SGA	Dopamine blockade → hyperprolactinaemia → ↓libido, ED, anorgasmia; also anticholinergic and anti-alpha-adrenergic effects
Antihistamines	H1 blockers, H2RAs	Anticholinergic effects → ↓arousal
Parkinson's medications	Dopamine agonists	Paradoxically can cause hypersexuality (↑dopamine in mesolimbic pathway) — a paraphilia-like presentation
Drugs of abuse	Alcohol, heroin, stimulants, marijuana	Alcohol: CNS depressant, ↓testosterone with chronic use; Heroin: ↓GnRH → ↓testosterone; Stimulants: acute ↑then chronic ↓function; Marijuana: ↓testosterone

Other organic causes ^[2]:
- ED of various causes (vascular, neurogenic, hormonal, anatomical)
- Menopausal changes (↓oestrogen → vaginal atrophy, ↓lubrication, dyspareunia)
- Neurologic disorders (spinal cord injury, MS, stroke)
- Endocrine disorders (hypothyroidism, hyperprolactinaemia, hypogonadism)
- Cardiovascular disease (shared risk factors with ED — both are endothelial dysfunction)

ED as a Sentinel Marker

Erectile dysfunction often precedes cardiovascular events by 3–5 years. Penile arteries (1–2mm diameter) are smaller than coronary arteries (3–4mm), so endothelial dysfunction manifests earlier in the penis. Always screen for cardiovascular risk factors in a man presenting with ED.

The aetiology is unknown, but several hypotheses have been proposed ^[2]:

Model	Explanation
Behavioural model	Sexual preference is shaped by events and reinforcement during development — e.g., if an early sexual experience is paired with an atypical stimulus, classical conditioning may establish that stimulus as arousing
Psychoanalytic model	Castration anxiety not resolved in childhood → fetish object represents the phallus (Freudian theory — largely historical, not evidence-based)
Biological model	Abnormal brain activity/structure, genetic predisposition — some neuroimaging studies show altered frontal-temporal function in paedophilia
Disease model	Those beginning late in life may be secondary to dementia, other organic disorders, and their treatment (e.g., dopamine agonist for Parkinson's disease is associated with abnormal sexual behaviours — hypersexuality, paraphilia-like behaviours) ^[2]

Late-Onset Paraphilia = Think Organic

If a previously normal individual develops paraphilic behaviour in middle or old age, ALWAYS consider an organic cause: frontal lobe dementia, brain tumour (especially orbitofrontal), Parkinson's disease treatment (dopamine agonists), or other disinhibiting conditions.

5. Classification

Note: ICD-11 (current) and DSM-5-TR are the classification systems to know. ICD-10 is being phased out but still referenced in some Hong Kong settings.

DSM-5-TR	ICD-10 (Legacy)	Phase Affected
Sexual desire/arousal disorders
Female sexual interest/arousal disorder	Lack or loss of sexual desire; Sexual aversion	Desire/Excitement
Male hypoactive sexual desire disorder	Lack or loss of sexual desire	Desire
Erectile disorder	Failure of genital response	Excitement
Orgasm disorders
Female orgasmic disorder	Orgasmic dysfunction	Orgasm
Delayed ejaculation	Orgasmic dysfunction	Orgasm
Premature ejaculation	Premature ejaculation	Orgasm
Sexual pain disorders
Genitopelvic pain/penetration disorder	Nonorganic dyspareunia; Nonorganic vaginismus	Pain-related
Substance/medication-induced sexual dysfunction	—	Any phase

^[2]

Additional important classification distinctions:

Lifelong vs. Acquired: Was the problem always present, or did it develop after a period of normal function?
Generalised vs. Situational: Does it occur in all situations, or only specific ones? (e.g., a man who cannot get an erection with his partner but has normal morning erections and erections during masturbation → likely psychogenic, not organic)
Severity: mild, moderate, severe

Paraphilias are broadly classified into two groups:

Abnormalities of Object of Sexual Interest	Abnormalities of the Sexual Act
Paedophilia: sexual fantasies/urges/behaviours involving children ( < 13 years; individual must be ≥ 16 and ≥ 5 years older than child)	Exhibitionism: exposure of genitals to unsuspecting strangers (typically for the shock reaction)
Fetishism: involving inanimate objects or non-erogenous body parts (e.g., shoes, leather, feet)	Voyeurism: observing unsuspecting people engaging in sexual activity or undressing
Transvestic fetishism: involving cross-dressing (sexual arousal from wearing opposite-sex clothing — NOT the same as gender dysphoria)	Frotteurism (French: frotter = to rub): rubbing genitalia against another person or fondling breasts of unwilling person (e.g., on crowded public transport — relevant in Hong Kong MTR context)
Zoophilia (bestiality): involving animals	Sexual sadism (from Marquis de Sade): infliction of physical or psychological suffering/humiliation on others
Necrophilia (Greek: nekros = dead + philia = love): involving corpses	Sexual masochism (from Leopold von Sacher-Masoch): infliction of suffering/humiliation on oneself

Paraphilia vs Paraphilic Disorder

DSM-5 makes an important distinction: Having a paraphilia (atypical sexual interest) is NOT in itself a disorder. It becomes a paraphilic disorder only when:

It causes clinically significant distress or impairment in the individual, OR
It involves personal harm or risk of harm to others (e.g., paedophilia, exhibitionism, frotteurism)

This distinction is crucial — it de-pathologises atypical sexual interests that are consensual and non-distressing.

6. Clinical Features

6.1 Sexual Dysfunctions — Symptoms and Signs

The clinical features of each sexual dysfunction are best understood by mapping them to the affected phase of the sexual response cycle:

Erectile Disorder

Symptoms:

Inability to attain or maintain an adequate erection during sexual activity
- Pathophysiology: Erection requires intact parasympathetic input (S2–S4) → pelvic splanchnic nerves → cavernous nerves → NO release from endothelium → cGMP → smooth muscle relaxation in corpora cavernosa → arterial inflow ↑ → venous compression against tunica albuginea → rigidity. Disruption at ANY point causes ED:
  - Vascular: atherosclerosis, DM vasculopathy → ↓arterial inflow
  - Neurogenic: DM neuropathy, spinal cord injury → ↓NO release
  - Hormonal: ↓testosterone, ↑prolactin → ↓central drive
  - Psychogenic: anxiety → ↑sympathetic tone → vasoconstriction → overrides parasympathetic vasodilation
Key distinguishing feature — psychogenic vs organic ED:

Feature	Psychogenic	Organic
Onset	Sudden	Gradual
Situational?	Yes (e.g., works with masturbation, morning erections preserved)	No (absent in all situations)
Morning erections	Present	Absent
Relationship to stress	Closely linked	Not linked
Age	Younger (typically < 40)	Older (typically > 40)
Associated factors	Depression, anxiety, relationship problems	DM, CVD, medications, smoking

Signs:

Vascular: ↓peripheral pulses, bruits, retinopathy (fundoscopy)
Neurogenic: ↓perineal sensation, ↓bulbocavernosus reflex, peripheral neuropathy signs
Hormonal: gynaecomastia, ↓testicular volume, ↓body hair, visual field defects (pituitary tumour)

Female Sexual Interest/Arousal Disorder (excitement component):

Absent or reduced vaginal lubrication and engorgement during sexual activity
- Pathophysiology: parasympathetic-mediated vasodilation → vaginal transudation (plasma filtrate through vaginal epithelium). Disrupted by ↓oestrogen (menopause), autonomic neuropathy, medications (anticholinergics), psychological factors

The cardinal feature across all paraphilias is recurrent, intense sexually arousing fantasies, urges, or behaviours involving atypical stimuli, over a period of ≥ 6 months.

Paraphilia	Core Clinical Feature	Pathophysiological Basis/Notes
Paedophilia	Sexual fantasies/urges/behaviours involving prepubescent children	Most have a specific age/gender preference; highest recidivism among paraphilias; often comorbid with other paraphilias
Fetishism	Sexual arousal from inanimate objects or non-genital body parts	Behavioural conditioning model: object becomes paired with sexual arousal during formative years
Transvestic fetishism	Sexual arousal from cross-dressing	Distinct from gender dysphoria — here the cross-dressing is specifically for sexual arousal, not gender expression; some may develop gender dysphoria over time
Exhibitionism	Exposure of genitals to unsuspecting strangers	The arousal comes from the victim's shock reaction, not from actual sexual contact
Voyeurism	Observing unsuspecting people undressing/engaging in sex	The secrecy and violation of privacy is the source of arousal
Frotteurism	Rubbing/touching an unwilling person	Typically in crowded settings (e.g., public transport) — relevant to Hong Kong context
Sexual sadism	Inflicting suffering/humiliation on another person	In extreme cases may overlap with forensic populations (e.g., sexual homicide)
Sexual masochism	Inflicting suffering/humiliation on oneself	Only paraphilia not predominantly male; risk of accidental injury/death (e.g., autoerotic asphyxiation)

Red flags for paraphilic disorders:
- Acting on urges with non-consenting persons
- Significant distress or functional impairment
- Escalation in frequency or severity
- Comorbid substance use (disinhibition)
- Forensic/legal involvement

8. Key Specific Conditions — Additional Detail

Cultural factors: Confucian values, modesty, shame about sexual topics → late presentation, under-reporting
Living conditions: small flats, multi-generational living → lack of privacy → environmental contributor to sexual dysfunction
Work culture: extremely long hours → fatigue, stress, ↓quality time with partner
Traditional medicine: many patients may seek Traditional Chinese Medicine (TCM) for sexual dysfunction before presenting to Western medicine
Legal considerations for paraphilias: exhibitionism, frotteurism, and voyeurism are criminal offences under Hong Kong law (Crimes Ordinance). Paedophilia is prosecuted under various ordinances including the Crimes Ordinance and Protection of Children and Juveniles Ordinance
Gender dysphoria services: limited public sector services (primarily QMH/PWH psychiatry), long waiting times; hormone therapy and surgery require rigorous psychiatric assessment; legal gender change requires full sex reassignment surgery in Hong Kong (the "W" case 2013 landmark ruling established that post-operative transgender individuals can marry in their affirmed gender)

High Yield Summary

Psychosexual Disorders — Key Points:

Three categories: Sexual dysfunctions (functional problem), Paraphilias (abnormal preference), Gender Dysphoria (identity–sex mismatch)
Sexual Response Cycle (4 phases): Desire → Excitement → Orgasm → Resolution. Each sexual dysfunction maps to a specific phase disruption.
Refractory period exists in males only — females can have multiple orgasms.
Aetiology of sexual dysfunction is ALWAYS biopsychosocial: Biological (DM is #1 organic cause of ED, medications — especially SSRIs/antihypertensives/antipsychotics), Psychological (performance anxiety creates a vicious cycle, depression — 50% have SD), Sociocultural (relationship, environment, cultural)
Psychogenic vs Organic ED: Preserved morning erections + situational dysfunction = psychogenic.
Paraphilias: ALL mainly in males (except masochism). Late-onset = think organic (dementia, dopamine agonists). Paraphilia ≠ disorder unless causing distress/harm.
Gender Dysphoria: Gender identity formed by age 3; 39% MZ concordance; atypical brain differentiation from prenatal sex hormones; management follows SOC guidelines (psychological assessment → counselling → real-life experience → hormones → surgery). NOT about making identity match assigned sex.
Assessment of SD: Define the problem, sexual Hx (morning erections, masturbation), PMHx, drug Hx, examination (vasculopathy, neuropathy, hormonal, genitals), investigations (hormones, TFT, prolactin).
Sensate Focus: graded touching tasks, ban on intercourse initially → reduces performance anxiety.
Vaginismus: phobic response → muscle spasm → gradual desensitisation with dilators.

Active Recall - Psychosexual Disorders

Differential Diagnosis of Psychosexual Disorders

The differential diagnosis of psychosexual disorders is fundamentally about answering one question: "Is this a primary psychosexual disorder, or is the sexual/gender symptom a manifestation of something else?" This requires systematic thinking across organic, psychiatric, substance-related, and relational domains.

Because the three categories of psychosexual disorders (sexual dysfunctions, paraphilias, gender dysphoria) have very different differential diagnoses, we'll address each systematically.

1. Differential Diagnosis of Sexual Dysfunctions

The core clinical challenge is distinguishing primary sexual dysfunction from sexual symptoms that are secondary to organic disease, medications, psychiatric illness, or relationship factors. This is not just academic — management is completely different depending on the cause.

Differential	Key Distinguishing Features	Why It Matters
General medical conditions	History of DM, CVD, neurological disease, endocrine disorder; abnormal examination findings (vasculopathy, neuropathy, hormonal signs); abnormal investigations (glucose, lipids, hormones, prolactin, TFT) ^[2]	Organic causes are treatable and may be sentinel markers for serious disease (e.g., ED preceding MI by 3–5 years). Must be excluded FIRST.
Substance/medication-induced	Temporal relationship between drug initiation and onset of dysfunction; improvement with dose reduction/cessation; known culprit drugs: SSRIs, TCAs, MAOIs, beta-blockers, CCBs, spironolactone, lithium, BZDs, FGA/SGA, antihistamines, alcohol, heroin, stimulants, marijuana ^[2]	Extremely common and often overlooked. Always take a meticulous drug history. SSRIs are the single most common medication cause.
Depressive disorder	Sexual dysfunction is extremely common in depression (~50%) — from the disease itself (anhedonia → ↓desire, psychomotor retardation → ↓arousal) AND from treatment (SSRIs) ^[2]. Look for: low mood, anhedonia, sleep/appetite disturbance, guilt, suicidal ideation. Sexual symptoms track with mood episodes.	If sexual dysfunction only occurs during depressive episodes and resolves between episodes, primary diagnosis is depression, not a separate sexual dysfunction.
Anxiety disorders	Performance anxiety is the most common psychological perpetuator of ED. GAD may cause generalised ↓desire. Social anxiety may impair intimacy. PTSD (especially from sexual trauma) can cause aversion, vaginismus, or arousal difficulties ^[4].	The vicious cycle: anxiety → sympathetic overdrive → vasoconstriction → ED → more anxiety. Breaking the anxiety is often the treatment.
Psychotic disorders	Schizophrenia: negative symptoms (apathy, avolition) → ↓desire; positive symptoms (paranoid delusions about partner) → avoidance of intimacy; antipsychotic treatment → hyperprolactinaemia → ↓libido, ED, anorgasmia ^[2]	Sexual dysfunction in psychosis is multifactorial (disease + medications). Must distinguish from the rare presentation of somatic delusions involving genitalia.
Somatoform disorders	Patient may present with genital pain or sexual complaints as part of broader somatisation. In somatic symptom disorder, the focus is on distress and maladaptive response to somatic symptoms. No organic explanation found but the patient's concern is disproportionate ^[5].	Key distinction: in somatoform disorders, the patient seeks diagnosis and relief from perceived physical symptoms, not specifically complaining about sexual function per se.
Relationship/contextual factors	Dysfunction is situational — e.g., occurs only with partner but not during masturbation; temporal relationship with relationship deterioration; partner confirms conflict/communication problems ^[2]	"Sex is the barometer of a relationship." If the dysfunction is purely situational and relational, couples therapy is the treatment, not medication.
Normal ageing	Gradual decline in sexual desire, arousal, and frequency is physiologically normal with age (↓testosterone, ↓oestrogen, ↓vascular compliance). Becomes pathological only when it causes distress.	Do not over-pathologise normal ageing. A 75-year-old with reduced libido who is not distressed does not have a "disorder."
Hypogonadism	Low testosterone (male or female) from any cause: primary (testicular/ovarian failure), secondary (pituitary — check prolactin, FSH, LH), or functional (chronic illness, obesity, opioids). Presents with ↓libido, fatigue, ↓body hair, ↓muscle mass.	Always check sex hormones and prolactin. Hyperprolactinaemia (from pituitary adenoma or antipsychotics) is a treatable cause.
Pelvic/genital pathology	For dyspareunia specifically: must exclude endometriosis, ovarian cysts, PID, vaginal atrophy, Bartholin's cyst, vulvitis, Peyronie's disease, phimosis ^[2]	A thorough pelvic/genital examination is mandatory before diagnosing a psychosexual pain disorder.

The 50% Rule for Depression

Approximately 50% of patients with depression have sexual dysfunction — from the disease itself OR its medications ^[2]. This means: (1) Always screen for depression in sexual dysfunction, and (2) Always ask about sexual side effects when prescribing antidepressants. The irony is that the treatment for depression (SSRIs) often worsens the sexual dysfunction, creating a clinical dilemma.

Within the category of sexual dysfunctions, the key is mapping the complaint to the correct phase of the sexual response cycle:

Complaint	Phase	Disorder	Key Differentiating Point
"I don't feel like having sex"	Desire	Hypoactive sexual desire disorder	Reduced fantasies AND desire; distinguish from sexual aversion (active disgust/avoidance, often trauma-related)
"I can't get/maintain an erection" / "I don't get aroused"	Excitement	Erectile disorder / Female arousal disorder	In males: psychogenic vs organic (morning erections preserved?). In females: distinguish from ↓desire (she may desire sex but cannot become physically aroused)
"I come too quickly"	Orgasm	Premature ejaculation	Ejaculation within ~1 min (lifelong) or ≤ 3 min (acquired); must cause distress
"I can't reach orgasm"	Orgasm	Delayed ejaculation / Female orgasmic disorder	Distinguish from ↓desire (patient is aroused but cannot climax) and from medication effect (SSRIs)
"It hurts during sex"	Pain	Genitopelvic pain/penetration disorder	Superficial vs deep pain; with or without muscle spasm (vaginismus component); must exclude organic pelvic pathology

Situational vs Generalised — The Most Important Distinction

If a sexual dysfunction is situational (e.g., ED only with partner but normal morning erections and masturbation), it is almost certainly psychogenic or relational, not organic. If it is generalised (present in ALL situations including spontaneous erections), think organic. This single distinction drives the entire workup direction.

The differential is narrower but carries significant forensic implications — getting this wrong has legal consequences ^[2].

Differential	Key Distinguishing Features
Normal sexual variation	DSM-5 distinguishes paraphilia (atypical interest) from paraphilic disorder (causes distress or involves harm to others). Consensual, non-distressing atypical interests (e.g., consensual BDSM between adults) are NOT disorders.
Organic/neurological disease	Late-onset paraphilic behaviour (especially in middle-aged/elderly) → must consider frontal lobe dementia, brain tumour (orbitofrontal), Huntington's disease, or dopamine agonist therapy for Parkinson's disease ^[2]. The mechanism: loss of frontal inhibitory control or excessive dopaminergic stimulation of the mesolimbic reward pathway → disinhibited sexual behaviour.
Intellectual disability	May display inappropriate sexual behaviour due to impaired social judgement, not true paraphilia. The distinction: there is no specific pattern of deviant arousal, just poor behavioural regulation.
Substance intoxication	Alcohol, stimulants, or other disinhibiting substances may lead to inappropriate sexual behaviour. Key: the behaviour only occurs during intoxication and is not a persistent pattern.
Mania	Hypersexuality during manic episodes can include impulsive, disinhibited sexual behaviour that may resemble paraphilia. Key: it is episodic, occurs only during mood episodes, and resolves with treatment of mania ^[6].
Psychotic disorders	Rarely, sexual delusions or command hallucinations may drive inappropriate sexual behaviour. The behaviour is driven by psychotic symptoms, not by a persistent pattern of deviant arousal.
Personality disorders (especially antisocial, borderline)	Impulsive, risky sexual behaviour is common in cluster B personality disorders. Distinguished from paraphilia by: no specific pattern of deviant arousal; sexual acting-out is part of broader impulsivity and interpersonal dysfunction.
OCD with sexual obsessions	Patients with OCD may have intrusive, unwanted sexual thoughts (e.g., about children, same-sex, taboo acts) that are ego-dystonic — they find them repulsive and distressing. In paraphilia, the fantasies are ego-syntonic — they are arousing and desired (at least some of the time) ^[7]. This distinction is critical — OCD patients with sexual obsessions often fear they are "perverts" but they are NOT paraphilic.
Gender dysphoria vs transvestic fetishism	Cross-dressing in transvestic fetishism is specifically for sexual arousal. In gender dysphoria, cross-dressing reflects gender expression and is not primarily sexually motivated ^[2]. Some individuals with transvestic fetishism may later develop gender dysphoria.

Late-Onset Paraphilia = Always Organic Until Proven Otherwise

If someone with a previously normal sexual history develops paraphilic behaviour after age 40–50, ALWAYS investigate for organic causes: frontotemporal dementia, brain tumours, Parkinson's disease medication (dopamine agonists), or other causes of frontal disinhibition ^[2]. This has forensic as well as clinical implications.

Differential	Key Distinguishing Features
Gender non-conformity	NOT the same as gender dysphoria. A person can be gender non-conforming (e.g., a boy who likes traditionally feminine activities) without experiencing distress about their gender identity. Gender dysphoria requires persistent discomfort with biological sex and clinically significant distress ^[2].
Transvestic fetishism	Cross-dressing is for sexual arousal, not gender expression. The individual identifies with their assigned gender. However, some may develop gender dysphoria over time ("secondary gender dysphoria") ^[2].
Body dysmorphic disorder (BDD)	In BDD, the person is preoccupied with a perceived defect in physical appearance, which may include genital appearance. However, BDD does not involve a desire to be another gender — the distress is about the appearance of a specific body part, not about gender identity.
Psychotic disorders	Very rarely, a patient may have a delusion of being the opposite sex (e.g., "I have been transformed into a woman"). This is a delusional belief, not gender dysphoria. Key: it occurs in the context of other psychotic symptoms, onset is usually acute, and it resolves with antipsychotic treatment.
Disorders of sex development (DSD / intersex conditions)	Individuals with ambiguous genitalia, chromosomal anomalies (e.g., Klinefelter's 47,XXY, Turner's 45,X, congenital adrenal hyperplasia) may have gender identity questions. These are medically distinct from gender dysphoria in individuals with typical sex development, though gender dysphoria can coexist.
Homosexuality	Sexual orientation (who you are attracted to) is NOT the same as gender identity (who you are). A gay man identifies as male; a transgender woman may be attracted to men or women. These are independent dimensions. Homosexuality is NOT a disorder.
Normal childhood gender exploration	Young children frequently engage in cross-gender play and experimentation. This is developmentally normal. Gender dysphoria in children requires a persistent, insistent pattern — not just occasional role-play. Many children with gender non-conforming behaviour desist by adolescence ^[2].
Autism spectrum disorder (ASD)	Higher rates of gender diversity are noted in individuals with ASD. Careful assessment is needed to ensure the individual understands the concept of gender identity and that the dysphoria is genuine, not a manifestation of rigid thinking or social difficulties.

Key Principle: Assess Comorbidity Before Attributing Everything to Gender Dysphoria

Gender dysphoria has significantly increased comorbid Axis I disorders, especially mood and anxiety disorders ^[2]. Before confirming a diagnosis, one must rule out and treat any significant comorbid mental illness that might be contributing to identity confusion or distress. This does NOT mean denying the patient's experience — it means ensuring a thorough assessment. This is emphasised in the SOC guidelines ^[2].

Some differentials apply across all three categories:

Cross-Cutting Differential	Relevance
Substance use disorders	Alcohol: acute disinhibition (paraphilia-like behaviour), chronic ↓testosterone (sexual dysfunction), chronic personality change. Stimulants: acute hypersexuality, chronic dysfunction. Opioids: ↓GnRH → hypogonadism → ↓desire ^[2].
Medications	SSRIs → sexual dysfunction; antipsychotics → hyperprolactinaemia → sexual dysfunction; dopamine agonists → hypersexuality/paraphilia-like behaviour ^[2].
Personality disorders	Borderline PD: identity disturbance may include confusion about gender or sexual identity; impulsive sexual behaviour may mimic paraphilia. Antisocial PD: sexual offending may overlap with paraphilia.
Factitious disorder / Malingering	Rarely, patients may fabricate or exaggerate sexual symptoms (factitious: for the sick role; malingering: for external gain, e.g., legal proceedings). Consider if the presentation is inconsistent or if there is secondary gain ^[5].
Normal stress reactions and adjustment disorder	Acute stress, bereavement, major life change → transient sexual dysfunction. If ≤ 3 months and below threshold for specific disorder → adjustment disorder, not primary sexual dysfunction ^[4].

Presenting Complaint	Think About	Key Distinguishing Feature
↓ Libido	Depression, hypogonadism, hyperprolactinaemia, medications, relationship issues, normal ageing	Is there a mood disorder? Check hormones. Is it situational?
Erectile dysfunction	DM, CVD, medications, performance anxiety, depression, neurological disease	Morning erections preserved? Situational? Drug history?
Premature ejaculation	Primary (lifelong, serotonergic), secondary (anxiety, ED, prostatitis, thyroid)	Lifelong vs acquired? Comorbid ED? Check TFT.
Dyspareunia/vaginismus	Organic pelvic pathology, atrophic vaginitis, infection, endometriosis, phobic response, PTSD	Superficial vs deep? Examination findings? Trauma history?
Paraphilic behaviour	Primary paraphilia, organic disinhibition, substance use, mania, OCD with sexual obsessions, PD	Age of onset? New medications? Ego-syntonic vs dystonic?
Gender dysphoria	True GD, gender non-conformity, transvestic fetishism, BDD, psychosis, DSD, normal childhood play	Persistent and insistent? Causes distress? Cross-gender identification vs arousal?

High Yield Summary — Differential Diagnosis of Psychosexual Disorders

Sexual dysfunctions: Always exclude organic (DM #1, CVD), medication-induced (SSRIs #1), psychiatric (depression ~50% have SD), and relational causes before diagnosing primary sexual dysfunction.
Situational vs Generalised is the most important clinical distinction for sexual dysfunction — situational = likely psychogenic/relational; generalised = likely organic.
Paraphilias: Distinguish from OCD with sexual obsessions (ego-dystonic vs ego-syntonic), organic disinhibition (late-onset = always investigate), mania, substance use, and personality disorders.
Late-onset paraphilia = organic until proven otherwise (frontotemporal dementia, dopamine agonists, brain tumour).
Gender dysphoria: Distinguish from gender non-conformity (no distress), transvestic fetishism (arousal-driven), BDD (appearance-focused), psychosis (delusional), and normal childhood exploration.
Always assess comorbid psychiatric illness — mood and anxiety disorders are highly comorbid with all psychosexual disorders, and treating these may resolve or improve sexual symptoms.
Drug history is essential — SSRIs, antipsychotics, antihypertensives, dopamine agonists, and substances of abuse are all common culprits.

Active Recall - Differential Diagnosis of Psychosexual Disorders

References

^[2] Senior notes: ryanho-psych.md (Sections 9.3, 9.3.2, 9.3.3) ^[4] Senior notes: ryanho-psych.md (Section 8.1.1 — Approach to Anxiety; Section 8.3 — PTSD differential) ^[5] Senior notes: ryanho-psych.md (Section 8.4 — Somatoform Disorders, approach to medically unexplained symptoms) ^[6] Senior notes: ryanho-psych.md (Section 7.2 — Differential diagnosis of mania) ^[7] Senior notes: ryanho-psych.md (Section 8.2 — OCD differential diagnoses)

Diagnostic Criteria, Diagnostic Algorithm, and Investigations for Psychosexual Disorders

The diagnosis of psychosexual disorders is fundamentally clinical — there is no blood test or scan that "confirms" a sexual dysfunction, paraphilia, or gender dysphoria. However, investigations are essential to exclude organic causes and identify treatable contributing factors. The diagnostic process follows a structured approach: history → examination → targeted investigations → application of diagnostic criteria.

1. Diagnostic Criteria

1.1 Sexual Dysfunctions — DSM-5-TR Criteria

All DSM-5-TR sexual dysfunction diagnoses share common structural elements ^[2]:

Universal DSM-5-TR requirements for all sexual dysfunctions:

Symptoms must be persistent or recurrent
Must be present for a minimum of approximately 6 months
Must cause clinically significant distress in the individual
Must not be better explained by a non-sexual psychiatric disorder, severe relationship distress, other significant stressors, or substance/medication effects
Must specify: lifelong vs acquired; generalised vs situational; severity (mild/moderate/severe)

Criterion	Detail
A	Persistently or recurrently deficient (or absent) sexual/erotic thoughts or fantasies AND desire for sexual activity
B	Symptoms persist for ≥ 6 months
C	Causes clinically significant distress
D	Not better explained by another mental disorder, medical condition, substance, or relationship factors
Specifiers	Lifelong/acquired; generalised/situational; mild/moderate/severe

Why this criterion matters: Note that BOTH fantasies AND desire must be reduced — a person who has fantasies but doesn't act on them may have other barriers (relationship, opportunity) rather than a desire disorder.

Criterion	Detail
A	Lack of, or significantly reduced, sexual interest/arousal as manifested by ≥ 3 of the following: (1) absent/reduced interest in sexual activity; (2) absent/reduced sexual/erotic thoughts or fantasies; (3) no/reduced initiation of sexual activity and typically unreceptive to partner's attempts; (4) absent/reduced sexual excitement/pleasure during sexual activity in ≥ 75% of encounters; (5) absent/reduced sexual interest/arousal in response to any internal or external sexual/erotic cues; (6) absent/reduced genital or non-genital sensations during sexual activity in ≥ 75% of encounters
B–D	As above (≥ 6 months, distress, exclusions)

Criterion

Detail

Lack of, or significantly reduced, sexual interest/arousal as manifested by ≥ 3 of the following: (1) absent/reduced interest in sexual activity; (2) absent/reduced sexual/erotic thoughts or fantasies; (3) no/reduced initiation of sexual activity and typically unreceptive to partner's attempts; (4) absent/reduced sexual excitement/pleasure during sexual activity in ≥ 75% of encounters; (5) absent/reduced sexual interest/arousal in response to any internal or external sexual/erotic cues; (6) absent/reduced genital or non-genital sensations during sexual activity in ≥ 75% of encounters

B–D

As above (≥ 6 months, distress, exclusions)

Why DSM-5 combined interest and arousal in females: Research showed that in women, desire and arousal are much more intertwined than in men — many women experience "responsive desire" (arousal precedes and generates desire) rather than "spontaneous desire." Separating them artificially missed many women's experiences.

Criterion	Detail
A	≥ 1 of the following on almost all (≥ 75%) occasions of sexual activity: (1) marked difficulty in obtaining an erection during sexual activity; (2) marked difficulty in maintaining an erection until completion of sexual activity; (3) marked decrease in erectile rigidity
B–D	As above

Why 75%: Occasional erectile difficulties are normal (fatigue, stress, alcohol). The threshold of ≥ 75% ensures we are capturing a genuine pattern, not isolated incidents.

Criterion	Detail
A	A persistent or recurrent pattern of ejaculation occurring during partnered sexual activity within approximately 1 minute following vaginal penetration and before the individual wishes it
B–D	As above
Note	For non-vaginal sexual activities, no specific time criteria established; clinical judgement applies. For lifelong PE the threshold is ~1 minute; for acquired PE, ≤ 3 minutes is clinically significant

Why the time criterion: Normative data show that the median intravaginal ejaculatory latency time (IELT) is ~5.4 minutes. An IELT of < 1 minute is below the 2.5th percentile and consistently associated with distress and poor sexual satisfaction.

Criterion	Detail
A	Either of the following on almost all (≥ 75%) occasions of partnered sexual activity: (1) marked delay in ejaculation; (2) marked infrequency or absence of ejaculation
B–D	As above

Criterion	Detail
A	≥ 1 of the following on almost all (≥ 75%) occasions: (1) marked delay in, infrequency of, or absence of orgasm; (2) markedly reduced intensity of orgasmic sensations
B–D	As above
Specifier	"Never experienced an orgasm under any situation" (for lifelong subtype)

Criterion	Detail
A	Persistent or recurrent difficulties with ≥ 1 of the following: (1) vaginal penetration during intercourse; (2) marked vulvovaginal or pelvic pain during vaginal intercourse or penetration attempts; (3) marked fear or anxiety about vulvovaginal or pelvic pain in anticipation of, during, or as a result of vaginal penetration; (4) marked tensing or tightening of the pelvic floor muscles during attempted vaginal penetration
B–D	As above

Criterion

Detail

Persistent or recurrent difficulties with ≥ 1 of the following: (1) vaginal penetration during intercourse; (2) marked vulvovaginal or pelvic pain during vaginal intercourse or penetration attempts; (3) marked fear or anxiety about vulvovaginal or pelvic pain in anticipation of, during, or as a result of vaginal penetration; (4) marked tensing or tightening of the pelvic floor muscles during attempted vaginal penetration

B–D

As above

Why DSM-5 merged dyspareunia and vaginismus: Clinically, pain, fear, and muscle spasm are so intertwined that separating them was artificial. Most patients present with a combination — pain causes fear, fear causes spasm, spasm causes more pain ^[2].

Criterion	Detail
A	A clinically significant disturbance in sexual function
B	Evidence from history, examination, or investigations that the dysfunction developed during or soon after substance intoxication/withdrawal OR the medication is known to cause the dysfunction
C	Not better explained by a non-substance-induced sexual dysfunction
Specifiers	With onset during intoxication; with onset during withdrawal; with onset after medication use

All paraphilic disorder diagnoses share a two-criterion structure ^[2]^[8]:

Criterion A: Recurrent and intense sexually arousing fantasies, sexual urges, or behaviours involving the specific paraphilic focus, over a period of at least 6 months

Criterion B: The individual has acted on these urges with a non-consenting person, OR the urges/fantasies cause clinically significant distress or impairment in social, occupational, or other functioning

Paraphilic Disorder	Criterion A Specifics	Criterion B Notes
Exhibitionistic disorder	Exposure of genitals to an unsuspecting person	Acting on urges = sufficient for diagnosis (non-consenting victim)
Voyeuristic disorder	Observing an unsuspecting person who is naked, undressing, or engaging in sexual activity	Acting on urges = sufficient
Frotteuristic disorder	Touching or rubbing against a non-consenting person	Acting on urges = sufficient
Sexual masochism disorder	Being humiliated, beaten, bound, or otherwise made to suffer	Requires distress/impairment (consensual masochism without distress is NOT a disorder)
Sexual sadism disorder	Physical or psychological suffering of another person	Acting on non-consenting person = sufficient
Paedophilic disorder	Sexual activity with a prepubescent child (generally age ≤ 13); individual must be ≥ 16 years and ≥ 5 years older than the child	Acting on urges = sufficient
Fetishistic disorder	Use of non-living objects or highly specific focus on non-genital body parts	Requires distress/impairment
Transvestic disorder	Cross-dressing	Requires distress/impairment; specifiers: with fetishism, with autogynephilia

Paraphilia ≠ Paraphilic Disorder — Critical Exam Distinction

DSM-5 explicitly states that having an atypical sexual interest (paraphilia) is NOT sufficient for a diagnosis. It becomes a disorder only when Criterion B is met — i.e., distress/impairment OR involvement of non-consenting persons/harm. This is an intentional de-pathologisation of consensual, non-distressing atypical sexuality. In an exam, always state both criteria.

1.3 Gender Dysphoria — DSM-5-TR Criteria [2]

Criterion	Detail
A	A marked incongruence between one's experienced/expressed gender and assigned gender, of ≥ 6 months duration, as manifested by ≥ 2 of the following: (1) marked incongruence between experienced gender and primary/secondary sex characteristics; (2) strong desire to be rid of one's primary/secondary sex characteristics; (3) strong desire for primary/secondary sex characteristics of the other gender; (4) strong desire to be of the other gender (or an alternative gender); (5) strong desire to be treated as the other gender; (6) strong conviction that one has typical feelings/reactions of the other gender
B	The condition is associated with clinically significant distress or impairment in social, occupational, or other areas of functioning
Specifier	With or without a disorder of sex development; post-transition

Criterion	Detail
A	Marked incongruence between experienced/expressed gender and assigned gender, ≥ 6 months, manifested by ≥ 6 of the following (must include criterion 1): (1) strong desire to be of the other gender or insistence that one IS the other gender; (2) strong preference for cross-dressing; (3) strong preference for cross-gender roles in make-believe play; (4) strong preference for toys/activities stereotypically used by the other gender; (5) strong preference for playmates of the other gender; (6) strong rejection of typically gender-congruent toys/activities; (7) strong dislike of one's sexual anatomy; (8) strong desire for primary/secondary sex characteristics matching experienced gender
B	Clinically significant distress or impairment

Criterion

Detail

Marked incongruence between experienced/expressed gender and assigned gender, ≥ 6 months, manifested by ≥ 6 of the following (must include criterion 1): (1) strong desire to be of the other gender or insistence that one IS the other gender; (2) strong preference for cross-dressing; (3) strong preference for cross-gender roles in make-believe play; (4) strong preference for toys/activities stereotypically used by the other gender; (5) strong preference for playmates of the other gender; (6) strong rejection of typically gender-congruent toys/activities; (7) strong dislike of one's sexual anatomy; (8) strong desire for primary/secondary sex characteristics matching experienced gender

Clinically significant distress or impairment

Why 6 of 8 for children but only 2 of 6 for adults?: The threshold is deliberately higher for children because gender non-conforming behaviour is common in childhood and many children desist. A higher bar reduces over-diagnosis. In contrast, by adolescence/adulthood, the presentation is typically more crystallised.

Diagnosis can be by any appropriately trained health professional under the latest guidelines (WPATH SOC-8) ^[2]. This is a deliberate de-gatekeeping measure — you do not need a specialist psychiatrist specifically, though in Hong Kong, referral to a psychiatrist with expertise in gender identity is standard practice.

Condition	ICD-11 Term	Key Change from ICD-10
Sexual dysfunctions	Sexual dysfunctions	Broadly similar to DSM-5; explicitly requires distress
Paraphilias	Paraphilic disorders	Similar two-criterion structure; emphasises harm/distress
Gender dysphoria	Gender Incongruence	Moved OUT of "Mental and Behavioural Disorders" chapter → into "Conditions related to sexual health" — a landmark de-psychiatrisation move

2. Diagnostic Algorithm

3. Investigation Modalities

3.1 Investigations for Sexual Dysfunctions

The purpose of investigations is threefold: (1) exclude organic causes, (2) identify treatable contributing factors, and (3) establish a baseline before treatment. Investigations should be targeted based on clinical suspicion from history and examination, not shotgun ^[2].

Investigation	What It Tells You	Key Findings and Interpretation
Renal function tests (RFT)	Chronic kidney disease causes sexual dysfunction via uraemia, anaemia, autonomic neuropathy, ↓testosterone, hyperprolactinaemia	↑Urea, ↑creatinine → CKD contributing to SD
Liver function tests (LFT)	Chronic liver disease → ↑SHBG → ↓free testosterone → ↓libido, ED; also ↑oestrogen (impaired hepatic metabolism) → gynaecomastia, feminisation	↑Bilirubin, ↑transaminases, ↓albumin → chronic liver disease
Alcohol level	Acute alcohol intoxication → CNS depression → ↓arousal; chronic alcohol → ↓testosterone, liver disease, neuropathy ^[2]	Elevated → may explain dysfunction; also screen with CAGE/AUDIT
Thyroid function tests (TFT)	Hypothyroidism → ↓libido, ED, delayed ejaculation, fatigue; Hyperthyroidism → premature ejaculation (↑sympathetic tone), ↓libido	↑TSH, ↓fT4 → hypothyroidism; ↓TSH, ↑fT4 → hyperthyroidism
Pituitary hormones (including prolactin)	Hyperprolactinaemia (from pituitary adenoma, antipsychotics, hypothyroidism) → directly suppresses GnRH → ↓LH/FSH → ↓testosterone → ↓libido, ED, anorgasmia	↑Prolactin → investigate cause (MRI pituitary if significantly elevated, review medications). Even mildly elevated prolactin can cause SD
Sex hormone profile	Testosterone (total AND free), oestradiol, FSH, LH, SHBG	↓Testosterone: primary hypogonadism if ↑FSH/LH (testicular failure); secondary if ↓FSH/LH (pituitary/hypothalamic cause). SHBG ↑ with age, liver disease, hyperthyroidism → ↓bioavailable testosterone even if total is "normal"
Fasting glucose / HbA1c	DM is the #1 organic cause of ED (vasculopathy + neuropathy) ^[2]	↑Glucose or HbA1c ≥ 6.5% → DM. Even pre-diabetes contributes
Lipid profile	Dyslipidaemia → atherosclerosis → penile vascular disease → ED	↑LDL, ↓HDL, ↑triglycerides → cardiovascular risk, treat aggressively
FBC	Anaemia → fatigue → ↓desire; chronic disease	↓Hb → investigate cause

^[2]

The Essential Sexual Dysfunction Blood Panel

Must-order in any sexual dysfunction workup ^[2]:

RFT, LFT, Alcohol
TFT
Pituitary hormones (including prolactin)
Sex hormone profile (testosterone, oestradiol, FSH, LH, SHBG)
Fasting glucose / HbA1c
Lipid profile

The mnemonic "RATS Have Sexy Lives": RFT, Alcohol/LFT, TFT, Sex hormones + prolactin, HbA1c, Lipids

Investigation	Indication	What It Measures	Key Findings
Nocturnal penile tumescence (NPT) testing	Distinguishing psychogenic from organic ED when clinical assessment is equivocal	Measures erections during REM sleep using a portable device (RigiScan) worn overnight for 2–3 nights	Normal NPT (3–5 episodes per night, rigidity > 60%, duration > 10 min) → psychogenic ED (the neurovascular mechanism is intact; the problem is psychological). Abnormal NPT → organic ED. This is the gold standard for this distinction because during REM sleep, psychological inhibition is removed.
Penile Doppler ultrasound	Suspected vasculogenic ED	Measures peak systolic velocity (PSV) and end-diastolic velocity (EDV) in cavernous arteries after intracavernosal injection of alprostadil (PGE1)	PSV < 25 cm/s → arterial insufficiency; EDV > 5 cm/s → venous leak (blood fills the corpora but drains out too quickly). Normal: PSV > 35 cm/s, EDV < 5 cm/s
Intracavernosal injection test	Assessing erectile capacity independent of neurological input	Direct injection of alprostadil into the corpus cavernosum	Full erection within 10 minutes that lasts > 30 minutes → intact vascular mechanism (neurogenic or psychogenic cause). Poor response → vasculogenic ED
Biothesiometry / nerve conduction studies	Suspected neurogenic ED (DM neuropathy, spinal cord lesion)	Measures penile vibration perception threshold; or formal nerve conduction studies of pudendal nerve	Elevated vibration threshold → peripheral neuropathy contributing to ED
Pelvic ultrasound (female)	Dyspareunia with suspected pelvic pathology	Assesses for ovarian cysts, endometriosis, fibroids, pelvic masses	Identifies organic causes of deep dyspareunia
Vaginal pH / swabs	Suspected infection or atrophic vaginitis contributing to dyspareunia	Vaginal pH, microscopy, culture	pH > 4.5 + thin epithelium → atrophic vaginitis; positive cultures → infection

Tool	Purpose	Key Features
International Index of Erectile Function (IIEF-5)	Standardised screening and severity grading for ED	5-item questionnaire; score 5–25; severe ED ≤ 7, mild ED 17–21
Female Sexual Function Index (FSFI)	Comprehensive assessment of female sexual function across 6 domains	19 items; domains: desire, arousal, lubrication, orgasm, satisfaction, pain; total score ≤ 26.55 suggests dysfunction
Premature Ejaculation Diagnostic Tool (PEDT)	Screening for PE	5 items; score ≥ 11 = PE likely
Patient Health Questionnaire (PHQ-9)	Screen for comorbid depression	9 items; ≥ 10 = moderate depression requiring treatment
Generalised Anxiety Disorder scale (GAD-7)	Screen for comorbid anxiety	7 items; ≥ 10 = moderate anxiety

Paraphilia diagnosis is almost entirely clinical — based on history (often corroborated by forensic/legal records). However, investigations may be relevant in specific contexts ^[2]:

Investigation	Indication	Purpose
Penile plethysmography (phallometry)	Forensic assessment (especially paedophilia)	Measures penile circumference changes in response to visual/auditory sexual stimuli. Can help identify patterns of deviant arousal. Controversial — ethical and privacy concerns; not universally used.
Neuroimaging (MRI brain)	Late-onset paraphilia, suspected organic cause	Rule out frontal lobe pathology (frontotemporal dementia, tumour) in new-onset paraphilic behaviour in middle-aged/elderly patients
Testosterone, LH, FSH	Baseline before anti-androgen therapy	Need pre-treatment levels to monitor response; also to exclude hypogonadism as confound
LFT, FBC, coagulation	Before pharmacotherapy (anti-androgens)	Cyproterone acetate is hepatotoxic — need baseline LFT
Cognitive screening (MMSE / MoCA)	Late-onset, suspected dementia	Screen for frontotemporal dementia or other neurodegenerative cause

Paraphilia Assessment Has Forensic Implications

When assessing paraphilias, remember two priorities ^[2]:

Diagnosis — which has forensic/legal implications (e.g., paedophilia → mandatory reporting obligations)
Risk assessment — risk to others, need to report to authorities

Document meticulously. In Hong Kong, if there is a credible risk of harm to identifiable persons (especially children), the clinician has a duty to report to the Social Welfare Department or police.

Gender dysphoria diagnosis is clinical — made by applying DSM-5/ICD-11 criteria during a comprehensive psychiatric assessment. There is no confirmatory investigation. However, investigations are relevant at specific stages:

Investigation	Stage	Purpose
Comprehensive psychiatric assessment	Initial	Rule out and treat any significant comorbid mental illness (mood, anxiety disorders are highly comorbid) ^[2]; distinguish from transvestic fetishism, BDD, psychosis, DSD
Karyotype	If DSD suspected	Rule out chromosomal abnormalities (47,XXY Klinefelter's, 45,X Turner's, etc.)
Baseline hormones	Before hormonal therapy	Testosterone, oestradiol, FSH, LH, prolactin, TFT — establish baseline for monitoring
LFT, lipids, FBC, coagulation	Before hormonal therapy	MtF: oestrogen therapy ↑risk of VTE, hepatotoxicity. FtM: testosterone → polycythaemia (↑RBC)
Bone densitometry (DEXA)	During hormonal therapy	Monitor bone health — especially in MtF on anti-androgens (↓testosterone → ↓bone density)
Prolactin	During MtF hormonal therapy	Oestrogen therapy can ↑prolactin → monitor for prolactinoma
Psychological assessment tools	Throughout	PHQ-9, GAD-7 for comorbid mood/anxiety; gender identity questionnaires

The investigation results should be interpreted in the context of the clinical picture. Here is a practical interpretation framework:

Finding	Interpretation	Next Step
↓ Total testosterone, ↑ FSH/LH	Primary hypogonadism (testicular failure — e.g., Klinefelter's, age-related, orchitis)	Testosterone replacement therapy; karyotype if young
↓ Total testosterone, ↓ FSH/LH	Secondary hypogonadism (pituitary or hypothalamic cause)	Check prolactin → if ↑, MRI pituitary (prolactinoma?). If normal prolactin, consider hypothalamic cause (stress, opioids, obesity)
↑ Prolactin	Hyperprolactinaemia	Review medications (antipsychotics, metoclopramide); if no medication cause → MRI pituitary. Prolactin > 200 μg/L strongly suggests macroprolactinoma
↑ TSH, ↓ fT4	Hypothyroidism	Treat with levothyroxine — may improve libido, ED, delayed ejaculation
↓ TSH, ↑ fT4	Hyperthyroidism	May cause premature ejaculation (↑sympathetic tone); treat underlying cause
↑ HbA1c / fasting glucose	Diabetes mellitus	Optimise glycaemic control; ED in DM is multifactorial (vascular + neurogenic)
Normal NPT + abnormal clinical ED	Psychogenic ED	Psychosexual counselling, sensate focus, address anxiety
Abnormal NPT + abnormal clinical ED	Organic ED	Further vascular/neurogenic workup; consider PDE5 inhibitor trial
PSV < 25 cm/s on Doppler	Arterial insufficiency	CVD risk factor modification; PDE5 inhibitor; consider vascular surgery if severe
EDV > 5 cm/s on Doppler	Venous leak	Poor response to PDE5 inhibitors; may need surgical correction or penile prosthesis

High Yield Summary — Diagnosis of Psychosexual Disorders

All DSM-5 sexual dysfunctions require: ≥ 6 months duration, clinically significant distress, not better explained by another disorder/substance/medical condition. Specify lifelong vs acquired, generalised vs situational.
Paraphilic disorders require TWO criteria: (A) recurrent intense atypical fantasies/urges/behaviours ≥ 6 months AND (B) distress/impairment OR involvement of non-consenting persons. Paraphilia without Criterion B is NOT a disorder.
Gender dysphoria in adults requires ≥ 2 of 6 features for ≥ 6 months + distress. In children, ≥ 6 of 8 features (higher threshold to avoid over-diagnosis). ICD-11 reclassified as "Gender Incongruence" outside of mental disorders.
Investigations for sexual dysfunction ^[2]: RFT, LFT, alcohol, TFT, pituitary hormones (prolactin), sex hormone profile, HbA1c, lipids. Specialist: NPT (psychogenic vs organic ED), penile Doppler (vascular ED).
NPT is the gold standard for distinguishing psychogenic from organic ED: normal NPT = intact neurovascular mechanism = psychogenic.
Morning erections preserved + situational dysfunction = psychogenic. This simple clinical observation often obviates expensive testing.
Late-onset paraphilia → MRI brain to exclude frontotemporal dementia or tumour.
Gender dysphoria diagnosis is clinical — investigations support pre-treatment workup, not diagnosis itself. Comprehensive psychiatric assessment to rule out comorbid Axis I disorders is essential.

Active Recall - Diagnostic Criteria and Investigations for Psychosexual Disorders

References

^[2] Senior notes: ryanho-psych.md (Sections 9.3, 9.3.2, 9.3.3) ^[8] Senior notes: ryanho-psych.md (Section 9.3 — DSM-5 vs ICD-10 classification table, paraphilic disorders)

Management of Psychosexual Disorders

Management of psychosexual disorders follows a core principle: treat the cause, not just the symptom. A man with ED from uncontrolled diabetes needs glycaemic optimisation, not just sildenafil. A woman with ↓desire from SSRI-induced dysfunction needs a medication review, not sex therapy alone. The biopsychosocial aetiology demands a biopsychosocial management approach — and in practice, most patients need a combination of strategies.

Let me walk through this systematically for each major category.

2. Management of Sexual Dysfunctions — Detailed

2.2 Sex Therapy — The Core Psychosexual Intervention

Sex therapy is a structured behavioural intervention based on the principle that sexual dysfunction is often maintained by anxiety, avoidance, and communication failure ^[2].

Core principles ^[2]:

Partners treated together — sex is a dyadic (couple) activity; treating one partner alone misses half the problem
Helped to communicate better about sexual relationship — many couples have never openly discussed what they want/enjoy
Education on anatomy and physiology of sexual intercourse — surprisingly effective; many people have poor understanding of normal sexual response

Sensate focus: a series of graded tasks → hierarchical series of structured touching opportunities with a focus on what must NOT yet be done and what is to be done → significantly reduces performance anxiety ^[2]

This is the cornerstone sex therapy technique, developed by Masters & Johnson. Here's why it works from first principles:

The problem: Performance anxiety creates a vicious cycle — fear of failure → sympathetic activation → vasoconstriction/↓arousal → failure → more fear
The solution: Remove the pressure to perform by explicitly banning intercourse in early stages. Paradoxically, when there is nothing to "fail" at, anxiety drops and natural arousal can return

Stage	What To Do	What Is Banned	Purpose
Stage 1: Non-genital sensate focus	Take turns touching partner's body, focusing on sensation and pleasure	Genital touching, intercourse	Rediscover physical intimacy without pressure; learn what feels good
Stage 2: Genital sensate focus	Include genital touching, but with focus on exploration not orgasm	Intercourse, orgasm as a goal	Build comfort with genital contact; ↓performance anxiety around genital arousal
Stage 3: Containment	Brief vaginal containment of penis without movement	Thrusting, orgasm	Desensitise to penetration (especially useful for vaginismus and PE)
Stage 4: Gradual intercourse	Slow progression to movement and intercourse	No restrictions, but maintain focus on pleasure not performance	Reintroduce full sexual activity with new non-anxious associations

Sexual Dysfunction	Specific Exercise	Mechanism
Female orgasmic disorder	Exercises in sexual fantasy and masturbation, sometimes with a vibrator or dildo ^[2]	Teaches the woman to identify what stimulation leads to orgasm in a low-pressure setting; she can then communicate this to her partner. Masturbation removes performance anxiety and interpersonal variables.
Premature ejaculation	Squeeze technique: woman squeezes the glans of her partner's penis for a few seconds when he feels ejaculation is imminent. Start-stop method: stimulation is halted and arousal allowed to subside when the man feels ejaculation is imminent; the process is then repeated. Quiet vagina: man keeps penis motionless in vagina for increasing periods before ejaculating ^[2]	All three techniques work by training the man to recognise the point of "ejaculatory inevitability" and learn to control arousal at that threshold. Repeated practice raises the ejaculatory threshold over time.
Vaginismus	Desensitisation, first by finger insertion followed by dilators of increasing size ^[2]	Systematic desensitisation — the same principle used in treating phobias. Graded exposure to the feared stimulus (vaginal penetration) in a controlled, relaxed setting extinguishes the conditioned fear–spasm response. Patient starts with own finger → small dilator → progressively larger → eventually partner involvement.

Sensate Focus — The Most Important Concept in Sex Therapy

Sensate focus works because it attacks the root cause of most psychogenic sexual dysfunction: performance anxiety. By banning the "goal" (intercourse/orgasm), you remove the possibility of "failure," which breaks the anxiety–failure cycle. The focus shifts from "performing" to "experiencing." This is elegant behavioural therapy — simple in concept but transformative in practice ^[2].

2.3 Pharmacotherapy for Specific Sexual Dysfunctions

Treatment	Mechanism	Indication	Contraindications / Cautions	Key Points
PDE5 inhibitors (sildenafil, tadalafil, vardenafil, avanafil)	Inhibit phosphodiesterase type 5 → ↓breakdown of cGMP → sustained smooth muscle relaxation in corpora cavernosa → ↑blood flow → erection. Note: requires sexual stimulation to initiate NO release — they enhance, not create, erections	First-line pharmacotherapy for ED of any cause (organic, psychogenic, mixed)	Absolute: concurrent nitrate therapy (glyceryl trinitrate, isosorbide mononitrate) → profound hypotension → death. Caution: recent MI/stroke ( < 6 months), unstable angina, severe hepatic impairment, retinitis pigmentosa, anatomical penile deformity	Sildenafil: take 1hr before, lasts 4–6hrs. Tadalafil: longer-acting (36hrs), can be taken daily (2.5–5mg) — "the weekend pill." Side effects: headache, flushing, dyspepsia, visual disturbance (blue tinge — PDE6 cross-reactivity in retina), nasal congestion
Intracavernosal injection (alprostadil / PGE1)	Direct injection of prostaglandin E1 into corpus cavernosum → ↑cAMP → smooth muscle relaxation → erection independent of nerve input	Second-line: when PDE5i fails or is contraindicated; neurogenic ED (spinal cord injury)	Sickle cell disease (risk of priapism), penile fibrosis, concurrent anticoagulation (relative)	Patient self-injects. Risk of priapism (erection > 4 hours — medical emergency requiring aspiration), penile fibrosis with repeated use, pain at injection site
Intraurethral alprostadil (MUSE)	PGE1 pellet inserted into urethra → absorbed → local vasodilation	Alternative to injection for patients who refuse needles	As above	Less effective than injection; can cause urethral pain/bleeding
Vacuum erection device (VED)	Negative pressure draws blood into penis → constriction ring at base traps blood → maintains erection	Non-pharmacological option; useful when drugs contraindicated (e.g., on nitrates)	Manual dexterity issues, severe Peyronie's disease	Can feel "mechanical"; erection is cooler than natural (blood is venous, not arterial). Ring must be removed within 30 mins to prevent ischaemia
Penile prosthesis	Surgically implanted device — inflatable (hydraulic pump) or malleable (semi-rigid rods)	Last resort: when all other treatments have failed	Active infection, unrealistic expectations	High satisfaction rates (> 80%) when selected appropriately. Irreversible — destroys natural erectile tissue. Infection risk ~2–3%
Testosterone replacement	Restores testosterone in hypogonadal men → ↑libido, may improve erections	Only if documented hypogonadism (low testosterone)	Prostate cancer (testosterone fuels growth), severe sleep apnoea, polycythaemia (Hct > 54%), breast cancer	Available as: gel (daily), injection (2–4 weekly), patch. Monitor PSA, haematocrit, LFT, lipids

PDE5i + Nitrates = Death

NEVER prescribe PDE5 inhibitors with nitrates. Both cause vasodilation via the NO-cGMP pathway — combined effect → catastrophic systemic vasodilation → profound refractory hypotension → cardiovascular collapse → death. This includes ALL forms of nitrates: GTN spray, isosorbide mononitrate, isosorbide dinitrate. Also be cautious with alpha-blockers (additive hypotension). Always ask about cardiac medications before prescribing.

Treatment	Mechanism	Indication	Key Points
SSRIs (paroxetine, sertraline, fluoxetine, citalopram) — daily or on-demand	↑Serotonin at ejaculatory centre in lumbosacral cord → ↑ejaculatory threshold → delay ejaculation. The same mechanism that causes "sexual dysfunction" as a side effect of SSRIs is harnessed therapeutically here	First-line pharmacotherapy for PE	Paroxetine has strongest effect (↑IELT by ~8x). Daily dosing more effective than on-demand. Takes 1–2 weeks for full effect. Side effects: nausea, drowsiness, ↓libido (paradoxically)
Dapoxetine (short-acting SSRI)	Same as above but designed for on-demand use (rapid onset, short half-life ~1.5 hours)	On-demand treatment of PE	Take 1–3 hours before intercourse. Specifically licensed for PE (unlike other SSRIs which are off-label). Side effects: nausea, dizziness, headache. Contraindicated with MAOIs, potent CYP3A4 inhibitors
Topical anaesthetics (lidocaine/prilocaine cream — EMLA)	Local anaesthetic effect on penile glans → ↓sensory input → ↓ejaculatory reflex	Adjunct or alternative when SSRIs not tolerated	Apply 20–30 min before intercourse, wash off before penetration (otherwise numbs partner). Must use condom if not washed off
Clomipramine (TCA)	Serotonergic + noradrenergic effects → ↑ejaculatory threshold	Second-line (more side effects than SSRIs)	More anticholinergic side effects. Can be used on-demand (25mg 4–6hrs before)
Behavioural techniques (squeeze, start-stop, quiet vagina)	As described above ^[2]	First-line non-pharmacological	Often combined with pharmacotherapy for best results

Treatment	Mechanism	Indication	Key Points
Topical oestrogen (vaginal cream/pessary/ring)	Restores vaginal epithelial thickness, ↑blood flow, ↑lubrication, normalises pH	Dyspareunia/arousal difficulty due to vulvovaginal atrophy (post-menopausal)	Minimal systemic absorption → safe even when systemic HRT is contraindicated. First-line for genitourinary syndrome of menopause
Systemic HRT (oestrogen ± progesterone)	Replaces declining oestrogens → improves desire, arousal, lubrication, reduces hot flushes (which disrupt sleep/mood → affect desire)	Peri/postmenopausal women with multiple menopausal symptoms including sexual dysfunction	Risks: ↑breast cancer, VTE, stroke (with prolonged use). Use lowest effective dose for shortest duration. Contraindicated: history of breast cancer, active VTE, liver disease
Testosterone (off-label in females)	↑Libido — testosterone is the primary driver of sexual desire in both sexes	Hypoactive sexual desire disorder in postmenopausal women not responding to HRT alone	Evidence growing but still off-label in most jurisdictions. Transdermal patch/gel preferred. Monitor for virilising effects (acne, hirsutism, voice deepening)
Flibanserin	5-HT1A agonist + 5-HT2A antagonist → ↑dopamine and norepinephrine, ↓serotonin in prefrontal cortex → ↑desire	HSDD in premenopausal women	Daily dosing (not on-demand). Modest efficacy (~0.5 additional satisfying sexual events/month). Contraindicated with alcohol (severe hypotension/syncope), hepatic impairment, CYP3A4 inhibitors
Lubricants and moisturisers	Reduce friction → ↓pain during intercourse	Dyspareunia from any cause of inadequate lubrication	Simple, safe, first-line adjunct. Water-based or silicone-based
Pelvic floor physiotherapy	Teaches awareness and voluntary relaxation of pelvic floor muscles; manual techniques to release myofascial trigger points	Genitopelvic pain/penetration disorder, vaginismus	First-line physical intervention. Often combined with graded dilator therapy ^[2]

Strategy	Detail	When To Use
Wait and observe	Some tolerance develops to sexual side effects over weeks–months	Mild dysfunction, patient willing to wait, medication otherwise effective
Dose reduction	Lower dose may reduce side effects while maintaining efficacy	When on higher-than-minimum effective dose
Drug holiday	Skip medication on weekends (only for shorter half-life drugs like sertraline)	Stable patients, NOT with paroxetine (withdrawal) or fluoxetine (too long half-life anyway)
Switch to less sexually-impairing antidepressant	Bupropion (dopamine/norepinephrine — minimal sexual side effects), mirtazapine (noradrenergic/specific serotonergic — less sexual dysfunction), agomelatine (melatonergic — no sexual side effects), vortioxetine	When sexual side effects are intolerable and affecting compliance
Add antidote	Add bupropion to SSRI (↑dopamine counteracts serotonergic inhibition); or add PDE5i for ED specifically	When switching is not possible (e.g., the current antidepressant is the only one that works for their depression)

Bupropion — The Antidepressant That Helps, Not Hinders, Sex

Bupropion works via norepinephrine–dopamine reuptake inhibition (NDRI). Because it does NOT increase serotonin, it has minimal sexual side effects — and may even improve sexual function by ↑dopamine in the mesolimbic pathway. It is the go-to switch when SSRI-induced sexual dysfunction is the primary concern. Contraindications: seizure history, eating disorders (↓seizure threshold).

3. Management of Paraphilias [2]

Management: majority has limited evidence ^[2]

The approach to paraphilia management has three pillars: assessment, psychotherapy, and pharmacotherapy — with rehabilitation as an overarching goal.

Therapy	Mechanism	Detail
Behavioural therapy: covert sensitisation	Classical conditioning — pair paraphilic fantasy with humiliating consequences (imagined) ^[2]	Patient imagines paraphilic scenario → then imagines a highly aversive outcome (e.g., being arrested, family finding out, public humiliation). Repeated pairing ↓arousal to paraphilic stimulus
Aversion therapy	Classical conditioning — pair paraphilic fantasy with noxious stimulus ^[2]	e.g., unpleasant odour or taste presented when patient is exposed to paraphilic stimulus. Ammonia smelling salts or foul-tasting substances are used. Over time, the paraphilic stimulus becomes associated with displeasure rather than arousal
CBT	Cognitive restructuring of distorted beliefs that justify paraphilic behaviour	e.g., in paedophilia: "children enjoy sexual contact with adults" → challenged and restructured. Also addresses offence cycle, victim empathy, relapse prevention
Individual psychodynamic therapy ^[2]	Explores unconscious conflicts underlying paraphilic behaviour	Longer-term, less evidence-based, but may be useful for motivated individuals
Group therapy ^[2]	Peer accountability, confrontation of denial and minimisation	Particularly useful in sex offender treatment programmes

Drug	Mechanism	Indication	Key Considerations
SSRIs (e.g., fluoxetine, sertraline, paroxetine)	↑Serotonin → ↓sexual drive, ↓impulsivity, ↓obsessive-compulsive features of paraphilia; also treats comorbid depression/anxiety	First-line pharmacotherapy for most paraphilias — particularly exhibitionism, voyeurism, frotteurism ^[2]	Lower side effect profile than anti-androgens; mechanism here is dual — both ↓sexual arousal (serotonin inhibits sexual function) AND ↓compulsive element
Anti-androgens (cyproterone acetate, medroxyprogesterone acetate)	Competitive androgen receptor blockade (cyproterone) or ↓testosterone production (medroxyprogesterone) → ↓libido, ↓sexual arousal, ↓frequency of paraphilic fantasies	Higher-risk cases: particularly paedophilia and exhibitionism ^[2]; repeated sexual offending despite psychotherapy/SSRIs	Cyproterone: hepatotoxic (monitor LFT), depression, fatigue, gynaecomastia, ↓bone density, weight gain. Medroxyprogesterone: weight gain, depression, DVT risk. Both: reversible on cessation. Informed consent essential — "chemical castration" is ethically complex
GnRH agonists (leuprolide, triptorelin)	Initially stimulate then downregulate GnRH receptors → ↓↓LH/FSH → ↓↓testosterone to castrate levels. "Chemical castration" in its most potent form	Highest-risk / refractory cases — severe paedophilia, sexual sadism with violent offending, failure of other treatments ^[2]	Most potent suppression of testosterone. Side effects: hot flushes, ↓bone density (need DEXA monitoring), depression, cardiovascular risk. Very significant ethical/legal considerations. Often court-mandated in some jurisdictions

Pharmacotherapy for Paraphilias — Escalating Ladder

Think of it as an escalating ladder of potency and invasiveness:

SSRIs → mild ↓sexual drive, treats comorbidity, well-tolerated (first-line)
Anti-androgens → moderate ↓testosterone, significant side effects (second-line, higher risk)
GnRH agonists → maximal testosterone suppression, castrate levels (last resort, highest risk)

The choice depends on the severity of risk to others, not just the patient's distress.

4. Management of Gender Dysphoria [2]

Management: based on SOC-7 guideline (most influential) ^[2]

Note: The WPATH Standards of Care have been updated to SOC-8 (2022), but the senior notes reference SOC-7. The principles remain similar, with SOC-8 providing more flexibility and less rigid sequencing. The core pathway is:

4.2 Step-by-Step Detail

Direction	Agents	Effects	Monitoring
MtF (feminising)	Testosterone suppression: spironolactone, cyproterone acetate, GnRH agonist + Oestrogen (estradiol — oral, transdermal, or injectable) ^[2]	Breast development, fat redistribution to hips/thighs, ↓body hair, softer skin, ↓muscle mass, ↓libido, testicular atrophy, ↓spontaneous erections. Voice does NOT change (vocal cord changes from testosterone are irreversible)	Oestradiol, testosterone, prolactin (oestrogen ↑prolactin risk), LFT, lipids, coagulation (↑VTE risk), BMD. Monitor every 3–6 months initially
FtM (masculinising)	Androgens (testosterone — IM injection, transdermal gel/patch) ^[2]	Will develop secondary sexual characteristics: ↑clitoris size, ↑hair (facial and body), deep voice ^[2], ↑muscle mass, fat redistribution, acne, male-pattern baldness, cessation of menses, ↑libido	FBC (polycythaemia risk — testosterone ↑erythropoiesis), lipids (↑LDL, ↓HDL), LFT, testosterone levels. Haematocrit > 54% → dose reduction

Hormone	Contraindications
Oestrogen (MtF)	History of VTE or thrombophilia, active liver disease, oestrogen-sensitive malignancy (breast cancer), uncontrolled hypertension, migraine with aura (↑stroke risk)
Cyproterone acetate (MtF)	Hepatic impairment (hepatotoxic), meningioma (cyproterone associated with ↑risk), depression (can worsen)
Testosterone (FtM)	Polycythaemia (Hct > 54%), severe sleep apnoea, active liver disease, pregnancy (teratogenic — virilisation of female foetus)

Voice Changes Are Asymmetric

Testosterone deepens the voice irreversibly (thickens vocal cords) — so FtM individuals on testosterone will develop a deeper voice. However, oestrogen does NOT raise the voice — vocal cord thickening from puberty is irreversible. MtF individuals often need voice therapy (speech pathology) or, rarely, surgical vocal cord thinning (glottoplasty) to feminise their voice. This is a common source of distress for MtF individuals.

Direction	Procedures	Notes
MtF	Mammoplasty (if hormonal breast development insufficient), penectomy, orchidectomy, creation of vagina-like structure (vaginoplasty — typically penile inversion technique) ^[2]	Requires lifelong vaginal dilation to prevent stenosis. Facial feminisation surgery and tracheal shave (thyroid cartilage reduction) may also be desired but are usually not publicly funded
FtM	Mastectomy (chest masculinisation), ovariectomy (often with hysterectomy), phalloplasty (construction of a penis — complex, multi-stage, high complication rate) ^[2]	Alternatively: metoidioplasty (using hormonally-enlarged clitoris as a micropenis — simpler, fewer complications but smaller result). Scrotoplasty with testicular prostheses may also be performed

Indications for surgery:

Persistent, well-documented gender dysphoria
Capacity to make a fully informed decision and consent
Age of majority (18 in Hong Kong)
Completed ≥ 12 months of hormone therapy (if desired and medically appropriate)
Completed ≥ 12 months of living in the affirmed gender role
Well-controlled comorbid mental/medical conditions

Contraindications for surgery:

Unstable, uncontrolled psychiatric illness (active psychosis, severe untreated depression)
Inability to give informed consent
Unrealistic expectations
Medical conditions making surgery unacceptably high-risk

5.1 Management of Gender Dysphoria in Children and Adolescents

This is an area of active debate worldwide. The current approach in most guidelines:

Stage	Intervention	Indication	Reversibility
Prepubertal	Social transition (name, pronouns, clothing) + psychological support. NO medical intervention	Children with persistent gender dysphoria	Fully reversible
Early puberty (Tanner stage 2+)	GnRH agonists ("puberty blockers") — suppress puberty	Adolescents with persistent GD, onset of puberty causing distress	Fully reversible on cessation — puberty resumes. Purpose: buy time for the adolescent to mature and explore identity without the irreversible changes of endogenous puberty
Age ~16+	Gender-affirming hormones (oestrogen or testosterone)	After thorough assessment, if GD persists	Partially irreversible (e.g., voice deepening, breast development)
Age 18+	Surgical options	As above	Irreversible

Puberty Blockers — Buying Time, Not Making Decisions

GnRH agonists in early puberty work by downregulating the HPG axis → suppressing LH/FSH → halting pubertal development. They do NOT cause cross-sex changes — they simply press "pause." If stopped, endogenous puberty resumes. The rationale: prevent the distress and irreversible physical changes of the "wrong" puberty while the adolescent has more time for assessment and decision-making. Concerns: long-term bone density effects, potential impact on brain development (ongoing research).

Category	First-Line	Second-Line	Specialist/Last Resort
Sexual Dysfunctions	Treat underlying cause (organic, medication, psychiatric, relational); self-help; sensate focus; specific behavioural exercises ^[2]	Pharmacotherapy: PDE5i for ED, SSRIs for PE, topical oestrogen for atrophic vaginitis	Intracavernosal injection, vacuum devices, penile prosthesis, pelvic floor physio, surgery for pelvic pathology
Paraphilias	Assessment (diagnosis + risk); psychotherapy (behavioural therapy, CBT) ^[2]	SSRIs; anti-androgens for higher-risk cases ^[2]	GnRH agonists for highest-risk/refractory cases; forensic/legal involvement ^[2]
Gender Dysphoria	Psychological assessment + treat comorbidities; counselling and psychotherapy ^[2]	Real-life experience ≥ 1 year; hormonal therapy ^[2]	Gender-confirming surgery ^[2]

High Yield Summary — Management of Psychosexual Disorders

Sexual dysfunctions: Treat underlying cause FIRST (organic, medication, psychiatric, relational). For the majority: self-help, advice, reassurance ^[2]. Sex therapy = partners together, communication, education, sensate focus (graded touching tasks, ban intercourse initially → ↓performance anxiety).
Specific exercises ^[2]: Female orgasmic disorder → fantasy/masturbation/vibrator. PE → squeeze technique, start-stop, quiet vagina. Vaginismus → graded dilator desensitisation.
ED pharmacotherapy ladder: PDE5i (first-line) → intracavernosal injection → vacuum device → penile prosthesis. PDE5i + nitrates = ABSOLUTE contraindication (fatal hypotension).
PE pharmacotherapy: SSRIs first-line (paroxetine most potent); dapoxetine (on-demand short-acting SSRI); topical anaesthetics adjunct.
SSRI-induced sexual dysfunction: Switch to bupropion/mirtazapine, ↓dose, drug holiday, add PDE5i for ED.
Paraphilias: Evidence is limited. Assessment (diagnosis with forensic implication + risk). Psychotherapy (covert sensitisation, aversion therapy, CBT). Pharmacotherapy escalating ladder: SSRIs → anti-androgens → GnRH agonists. Rehabilitation.
Gender dysphoria (SOC guidelines): Psychological assessment (rule out comorbidities) → counselling (NOT conversion therapy) → real-life experience ≥ 1 year → hormonal therapy (MtF: oestrogen + anti-androgen; FtM: testosterone) → gender-confirming surgery. 86% FtM and 71% MtF report improved QoL ^[2].
FtM testosterone effects: ↑clitoris size, ↑hair, deep voice, ↑muscle, cessation of menses. MtF oestrogen does NOT change voice — voice therapy needed separately.

Active Recall - Management of Psychosexual Disorders

References

^[2] Senior notes: ryanho-psych.md (Sections 9.3, 9.3.2, 9.3.3)

Complications of Psychosexual Disorders

Complications of psychosexual disorders operate on multiple levels — the disorder itself causes psychological and relational harm, and the treatments carry their own risks. Think of this in a structured way: complications of the condition (untreated and treated), complications of treatment, and complications arising from societal/legal consequences.

1. Complications of Sexual Dysfunctions

Complication	Mechanism / Why It Occurs	Detail
Depression and anxiety	Sexual dysfunction → frustration, shame, sense of inadequacy → depressed mood. A bidirectional relationship exists: depression causes sexual dysfunction (~50% of depressed patients) ^[2], and sexual dysfunction causes/worsens depression. Each reinforces the other in a vicious cycle	In men, ED is independently associated with a 2–3x increased risk of developing major depressive disorder. The relationship is particularly pernicious because SSRIs prescribed for depression then worsen sexual dysfunction → patient stops antidepressant → depression relapses
Performance anxiety	One episode of sexual failure (e.g., erectile failure, premature ejaculation) → anticipatory anxiety about the next encounter → sympathetic overdrive → vasoconstriction (males) or ↓lubrication (females) → failure → reinforced anxiety ^[2]	This is the most common perpetuating factor in psychogenic sexual dysfunction. The cycle is self-reinforcing and can transform an isolated incident into a chronic disorder. The principle behind sensate focus therapy is specifically to break this cycle ^[2]
Low self-esteem and negative body image	Inability to perform sexually → internalised as personal failing → ↓self-worth → avoidance of intimacy → social withdrawal	Particularly relevant for men where masculinity is culturally tied to sexual performance, and for post-menopausal women with body image changes
Avoidance of intimacy	Repeated negative sexual experiences → conditioned avoidance of all physical and emotional intimacy → progressive distancing from partner	This avoidance can generalise beyond the bedroom — couples may avoid all physical affection (hugging, kissing, hand-holding) out of fear it will "lead somewhere"

Complication	Mechanism / Why It Occurs
Relationship deterioration and breakdown	Sexual dysfunction → frustration, resentment, communication breakdown between partners → relationship conflict → separation/divorce. The partner may feel rejected, unattractive, or blamed. The patient may withdraw or become defensive. Without intervention, the relationship suffers progressive damage
Infidelity	An unsatisfied partner may seek sexual fulfilment outside the relationship. Alternatively, the patient themselves may seek new partners to "prove" they can still function (as psychogenic dysfunction may be situational — works with a new partner but not the established one)
Non-consummation of marriage	Severe vaginismus or ED can result in complete inability to consummate a marriage — this has significant cultural, religious, and legal implications, particularly in Hong Kong where traditional Chinese and religious values place importance on consummation. Some couples present after years of unconsummated marriage
Infertility	Directly consequent when ED or vaginismus prevents penile-vaginal intercourse; premature ejaculation with ejaculation before penetration; anejaculation or retrograde ejaculation (e.g., post-prostatectomy) ^[2]. This adds an additional layer of distress, especially in cultures with strong expectations around procreation

Complication	Mechanism
Missed diagnosis of serious underlying disease	ED is a sentinel marker of cardiovascular disease — penile arteries (1–2mm) are smaller than coronary arteries (3–4mm), so endothelial dysfunction manifests 3–5 years earlier in the penis. A man who does not present with ED (due to embarrassment) misses the opportunity for early CVD intervention. Similarly, sexual dysfunction may be the presenting feature of undiagnosed DM, hypothyroidism, hyperprolactinaemia, or depression
Progression of underlying disease	If the organic cause (DM, CVD, hypogonadism) is not identified and treated, it progresses — DM vasculopathy worsens, CVD risk escalates, and the sexual dysfunction becomes more refractory to treatment
Medication non-compliance	Patients who develop sexual dysfunction from medications (SSRIs, antihypertensives, antipsychotics) may stop their medication without telling their doctor, leading to relapse of the primary condition (depression relapse, hypertensive crisis, psychotic relapse) ^[2]

The Dangerous Silence Around SSRI-Induced Sexual Dysfunction

Patients frequently do not volunteer sexual side effects of medications — they simply stop the drug. Studies show that up to 30–40% of patients on SSRIs discontinue treatment primarily due to sexual side effects, but only a fraction discuss this with their prescriber. This leads to depression relapse, which is far more dangerous than the sexual dysfunction itself. Always proactively ask about sexual side effects when prescribing SSRIs, antipsychotics, or antihypertensives ^[2].

Treatment	Complication	Mechanism / Why It Occurs
PDE5 inhibitors	Priapism (rare but serious — sustained erection > 4 hours)	Excessive cGMP-mediated smooth muscle relaxation → sustained venous occlusion → ischaemia of corporeal tissue. Medical emergency — requires aspiration of blood from corpora cavernosa ± injection of sympathomimetic (phenylephrine). If untreated: ischaemic necrosis → permanent ED
PDE5 inhibitors	Cardiovascular events	In patients with significant CVD: vasodilation → ↓preload → hypotension. Fatal with concurrent nitrates. Also: rarely — NAION (non-arteritic anterior ischaemic optic neuropathy) → sudden visual loss in one eye
Intracavernosal injection (alprostadil)	Priapism (more common than with PDE5i — up to 5%), penile fibrosis/scarring with repeated injections, pain at injection site, haematoma	Direct pharmacological vasodilation bypasses physiological control → if dose too high or patient hypersensitive, erection does not resolve spontaneously. Repeated needle trauma → fibrosis of corpora cavernosa → worsening ED over time
Penile prosthesis	Infection (2–3%), mechanical failure, erosion through skin/urethra, partner dissatisfaction, irreversibility	Implant acts as foreign body → biofilm formation → infection. Inflatable devices have hydraulic components that can malfunction. Implantation destroys natural erectile tissue — there is no going back
Testosterone replacement	Polycythaemia (↑Hct → ↑viscosity → ↑thrombotic risk), prostate stimulation (PSA monitoring required), sleep apnoea worsening, mood changes, acne, gynaecomastia (paradoxically — via aromatisation to oestrogen), liver toxicity (oral formulations)	Testosterone ↑erythropoiesis (stimulates EPO and acts directly on bone marrow). In the prostate: testosterone → DHT (via 5α-reductase) → stimulates prostate growth → concern for prostate cancer acceleration (though testosterone does not cause cancer, it may fuel existing subclinical cancer)
Hormonal therapy (menopausal HRT)	VTE, stroke, breast cancer (with prolonged combined oestrogen-progesterone use), gallbladder disease	Oestrogen → ↑hepatic production of clotting factors (II, VII, IX, X) → hypercoagulable state → VTE/PE/stroke. Prolonged oestrogen exposure → breast epithelial proliferation → ↑breast cancer risk

2. Complications of Paraphilias

Complication	Mechanism / Detail
Legal consequences	Many paraphilias involve non-consenting victims → criminal offences. In Hong Kong: exhibitionism (indecent exposure — Crimes Ordinance), voyeurism (loitering/peeping), frotteurism (indecent assault), paedophilia (various child protection ordinances, statutory rape). Conviction → imprisonment, sex offender registry, lifelong criminal record
Comorbid psychiatric illness	Paraphilias are associated with ↑rates of depression, anxiety, substance use disorders, and other paraphilias (comorbidity between different paraphilias is common — an individual with one paraphilia is likely to have others) ^[2]
Social ostracism and occupational loss	Discovery or conviction → loss of employment, social relationships, family. The stigma is profound and permanent
Physical injury (sexual masochism)	Autoerotic asphyxiation (self-strangulation during masturbation to enhance orgasm through hypoxia-induced euphoria) → accidental death. Estimated 250–1000 deaths/year in the US alone. Other self-injurious masochistic practices → tissue damage, infection
Substance use as self-medication	Distress from paraphilic urges or guilt after acting on them → alcohol/drug use to cope → substance use disorder → further disinhibition → ↑paraphilic acting-out (vicious cycle)

Complication	Detail
Psychological trauma to victims	Victims of exhibitionism, voyeurism, frotteurism, and especially sexual sadism and paedophilia may develop PTSD, depression, anxiety disorders, sexual dysfunction themselves, and difficulties with trust and intimacy. Childhood sexual abuse (paedophilia) has devastating long-term consequences: ↑risk of depression, PTSD, BPD, substance use, sexual dysfunction, and suicidality in adulthood
Physical harm to victims	Sexual sadism → physical injury, mutilation, death. Paedophilia → physical injury to children. Frotteurism → can escalate to more contact offences

Treatment	Complication	Mechanism
Anti-androgens (cyproterone acetate)	Hepatotoxicity (including fatal hepatic failure), depression, fatigue, gynaecomastia, ↓bone mineral density, weight gain, VTE, loss of fertility	Cyproterone is a potent progestogen with anti-androgen and glucocorticoid activity. Hepatotoxicity is idiosyncratic but dose-related — LFT monitoring is mandatory. ↓Testosterone → ↓bone formation (testosterone normally stimulates osteoblasts) → osteoporosis with chronic use
GnRH agonists (leuprolide, triptorelin)	Hot flushes, ↓bone mineral density (castrate testosterone levels → osteoporosis), depression, cardiovascular risk (metabolic syndrome, ↑LDL), loss of fertility, initial testosterone flare (paradoxical ↑testosterone for 1–2 weeks before suppression — may transiently ↑sexual urges)	GnRH agonist → initial stimulation of pituitary → ↑LH/FSH → ↑testosterone ("flare") → then continuous stimulation → receptor downregulation → ↓LH/FSH → ↓testosterone to castrate levels. The flare is dangerous — may need anti-androgen cover during the first 2 weeks
SSRIs	Sexual dysfunction (paradoxically — treating one sexual problem may create another), nausea, weight gain, emotional blunting, serotonin syndrome (if combined with MAOIs)	The same serotonergic mechanism that reduces paraphilic drive also reduces normal sexual function. Emotional blunting may reduce empathy development, which is counterproductive for rehabilitation

GnRH Agonist Testosterone Flare — A Dangerous Paradox

When a GnRH agonist is first started, it initially stimulates the pituitary (because it is an agonist) → surge of LH/FSH → transient increase in testosterone ("flare") for 1–2 weeks before receptor downregulation causes suppression. During this flare, a sex offender's urges may paradoxically increase. Anti-androgen cover (e.g., cyproterone) for the first 2–4 weeks is essential to prevent this. In prostate cancer treatment, this same flare can cause tumour flare symptoms.

3. Complications of Gender Dysphoria

Complication	Mechanism / Detail
Comorbid Axis I disorders, especially mood and anxiety disorders	Gender dysphoria is associated with significantly increased comorbid psychiatric illness ^[2]. This is likely multifactorial: minority stress (discrimination, stigma, family rejection, violence), body dysphoria (distress from physical characteristics incongruent with identity), social isolation, and possibly shared neurobiological vulnerability. Depression and anxiety rates are 2–3x higher than the general population
Suicidality and self-harm	Transgender individuals have among the highest rates of suicidal ideation and attempts of any population group. Studies show 40–45% lifetime prevalence of suicide attempts in transgender adults. Risk factors: family rejection, bullying/violence, lack of access to gender-affirming care, comorbid mental illness
Substance use disorders	As self-medication for dysphoria, distress, and social difficulties. Alcohol and cannabis are most common; stimulant and opioid use also elevated
Social and occupational dysfunction	Discrimination in employment, housing, healthcare; family estrangement; social isolation; bullying (especially in children/adolescents); difficulty maintaining relationships. In Hong Kong, legal protections for transgender individuals remain limited
Self-administered hormones / unsafe procedures	When access to legitimate medical care is limited (long wait times, cost, fear of gatekeeping), some individuals obtain hormones through unregulated channels (internet pharmacies, black market) or resort to dangerous self-procedures (e.g., silicone injections for breast augmentation). Risks: incorrect dosing, contaminated products, injection-site infections, silicone embolism

3.2 Complications of Treatment of Gender Dysphoria

Hormone Therapy	Complication	Mechanism
Oestrogen (MtF)	Venous thromboembolism (DVT/PE) — most serious acute risk	Oestrogen ↑hepatic synthesis of coagulation factors (especially factors II, VII, IX, X) and ↓antithrombin III → hypercoagulable state. Risk is dose-dependent and higher with oral vs transdermal route (first-pass hepatic effect). Smoking synergistically ↑risk
Oestrogen (MtF)	Cardiovascular events (stroke, MI)	Same hypercoagulable mechanism + potential effects on lipid profile (↑triglycerides, ↑HDL but also ↑clotting). Risk elevated especially in those > 40, smokers, and those with pre-existing CVD risk factors
Oestrogen (MtF)	Hyperprolactinaemia / prolactinoma	Oestrogen directly stimulates lactotroph proliferation in the anterior pituitary → ↑prolactin secretion → may cause or unmask prolactinoma. Requires monitoring of prolactin levels
Oestrogen (MtF)	Hepatotoxicity	First-pass hepatic metabolism of oral oestrogen → hepatocellular stress. Transdermal route safer for liver
Oestrogen (MtF)	Breast cancer (long-term risk)	Prolonged oestrogen exposure → epithelial proliferation in breast tissue → ↑risk over decades. MtF individuals should undergo breast cancer screening
Cyproterone acetate (MtF anti-androgen)	Hepatotoxicity, meningioma, depression	Cyproterone is hepatotoxic (idiosyncratic and dose-related — monitor LFT). Recent evidence shows ↑risk of meningioma with prolonged use (dose-cumulative). Depression: ↓testosterone contributes to low mood
Testosterone (FtM)	Polycythaemia	Testosterone ↑erythropoietin secretion from kidneys + direct stimulation of erythroid progenitors in bone marrow → ↑RBC mass → ↑haematocrit. If Hct > 54%: ↑blood viscosity → ↑risk of stroke, DVT, PE, MI. Monitor FBC regularly — dose reduce or phlebotomise if Hct rises
Testosterone (FtM)	Dyslipidaemia	Testosterone → ↑LDL, ↓HDL → ↑atherosclerotic cardiovascular risk over time
Testosterone (FtM)	Hepatotoxicity	Particularly with oral formulations (rare with injectable/transdermal)
Testosterone (FtM)	Acne and androgenic alopecia	Testosterone → DHT → stimulates sebaceous glands (acne) and activates hair follicle miniaturisation in genetically susceptible individuals (male-pattern baldness)
Testosterone (FtM)	Vaginal atrophy	Testosterone ↓local oestrogen effect on vaginal epithelium → thinning, dryness → dyspareunia if vaginal intercourse occurs. Topical oestrogen may be needed
GnRH agonists (puberty blockers in adolescents)	↓Bone mineral density, potential impact on height, uncertain effects on neurocognitive development	GnRH suppression → ↓sex steroids → ↓bone mineralisation during a critical window of skeletal development. Puberty is normally the period of peak bone accrual. Long-term BMD consequences are being studied. Reversible on cessation — puberty resumes and bone accrual catches up (though the extent of catch-up is debated)

Surgery	Complication	Detail
Vaginoplasty (MtF)	Neovaginal stenosis, fistula (rectovaginal or vesicovaginal), wound dehiscence, hair growth inside neovagina, loss of sensation, urinary complications (urethral stricture, spraying), need for lifelong dilation	The neovagina is created from penile skin (penile inversion technique) or bowel segment. It lacks natural self-maintenance — without regular dilation, the body treats it as a wound and it contracts/closes (wound contraction by myofibroblasts). Lifelong dilation is mandatory
Phalloplasty (FtM)	Highest complication rate of all gender-confirming surgeries (up to 40–60% require revision). Urethral fistula, urethral stricture, flap loss/necrosis, infection, loss of sensation, inability to achieve erection without prosthesis	Phalloplasty typically uses a radial forearm free flap or anterolateral thigh flap — a major microsurgical procedure. Urethral lengthening (to allow standing urination) is the most complication-prone component. Erectile function requires a penile prosthesis (inflatable or semi-rigid) — adding another layer of complication risk
Mastectomy (FtM)	Haematoma, seroma, nipple necrosis, unsatisfactory cosmetic result, persistent breast tissue (cancer screening still needed)	Relatively straightforward compared to other procedures but cosmetic expectations may not be fully met
Orchidectomy (MtF)	Irreversible loss of fertility, need for lifelong hormone replacement, surgical complications (bleeding, infection)	Removes the primary source of testosterone — patient becomes dependent on exogenous oestrogen for bone and cardiovascular health

Complication	Applies To	Detail
Impact on fertility	All categories	Sexual dysfunctions → inability to conceive naturally. Anti-androgens and GnRH agonists (paraphilias and GD) → ↓spermatogenesis/ovulation. Gender-confirming surgery → irreversible loss of reproductive capacity. Fertility preservation counselling (sperm banking, oocyte cryopreservation) should be offered before irreversible treatments
Stigma and discrimination	All categories	Patients with psychosexual disorders face significant stigma — from family, society, employers, and even healthcare professionals. In Hong Kong, traditional values create additional barriers. Stigma → delayed help-seeking → worse outcomes → ↑complications
Impact on children and families	All categories	Parental sexual dysfunction → relationship breakdown → impact on children's psychological wellbeing. Paraphilias involving children → devastating trauma. Gender dysphoria in a family member → family adjustment challenges, intergenerational conflict (especially relevant in traditional Chinese families)
Healthcare avoidance	All categories	Shame and stigma → patients avoid seeking medical care → late presentation for both the psychosexual disorder and for unrelated medical conditions (e.g., a transgender man avoiding cervical screening because of gender incongruence during examination)

Category	Key Complications of Disease	Key Complications of Treatment
Sexual Dysfunctions	Depression/anxiety (bidirectional), performance anxiety vicious cycle, relationship breakdown, infertility, missed diagnosis of CVD/DM, medication non-compliance ^[2]	PDE5i: priapism, fatal hypotension with nitrates. Injections: priapism, fibrosis. Prosthesis: infection, irreversibility. Testosterone: polycythaemia, prostate concerns
Paraphilias	Legal consequences (imprisonment), victim trauma (especially children), social ostracism, comorbid psychiatric illness, accidental death (masochism/autoerotic asphyxiation), substance use ^[2]	Anti-androgens: hepatotoxicity, depression, osteoporosis. GnRH agonists: testosterone flare, osteoporosis, CVD risk. SSRIs: sexual dysfunction
Gender Dysphoria	Comorbid mood/anxiety disorders, suicidality (40–45% lifetime SA), substance use, social/occupational dysfunction, self-administered hormones, healthcare avoidance ^[2]	Oestrogen: VTE, CVD, prolactinoma, breast cancer. Testosterone: polycythaemia, dyslipidaemia. Surgery: stenosis, fistula, loss of sensation, revision rates, irreversibility. Puberty blockers: ↓BMD

High Yield Summary — Complications of Psychosexual Disorders

Sexual dysfunction creates a self-perpetuating vicious cycle: dysfunction → performance anxiety → sympathetic overdrive → more dysfunction → depression → SSRI → worsened dysfunction → SSRI non-compliance → depression relapse ^[2].
ED is a cardiovascular sentinel — untreated ED misses a 3–5 year window for CVD prevention.
Medication non-compliance from sexual side effects is one of the most dangerous and underappreciated complications — always proactively ask about sexual function when prescribing SSRIs, antihypertensives, and antipsychotics ^[2].
PDE5i + nitrates = catastrophic hypotension → absolute contraindication.
Priapism (sustained erection > 4 hours) from PDE5i or intracavernosal injection = urological emergency → aspiration + phenylephrine; delay causes ischaemic necrosis and permanent ED.
Paraphilias: Legal consequences dominate. Autoerotic asphyxiation in masochism → accidental death. Paedophilia → devastating lifelong trauma to child victims. GnRH agonists have an initial testosterone flare requiring anti-androgen cover.
Gender dysphoria: Suicidality is the most serious complication (40–45% lifetime suicide attempts). Oestrogen → VTE (most serious acute complication of MtF hormones). Testosterone → polycythaemia (most serious of FtM hormones). Phalloplasty has highest surgical complication rate (40–60%). 86% FtM, 71% MtF report improved QoL post-treatment ^[2].
Fertility preservation counselling must be offered before any irreversible hormonal or surgical treatment.

Active Recall - Complications of Psychosexual Disorders

References

^[2] Senior notes: ryanho-psych.md (Sections 9.3, 9.3.2, 9.3.3)

High Yield Summary

Psychosexual Disorders — Key Points:

Three categories: Sexual dysfunctions (functional problem), Paraphilias (abnormal preference), Gender Dysphoria (identity–sex mismatch)
Sexual Response Cycle (4 phases): Desire → Excitement → Orgasm → Resolution. Each sexual dysfunction maps to a specific phase disruption.
Refractory period exists in males only — females can have multiple orgasms.
Aetiology of sexual dysfunction is ALWAYS biopsychosocial: Biological (DM is #1 organic cause of ED, medications — especially SSRIs/antihypertensives/antipsychotics), Psychological (performance anxiety creates a vicious cycle, depression — 50% have SD), Sociocultural (relationship, environment, cultural)
Psychogenic vs Organic ED: Preserved morning erections + situational dysfunction = psychogenic.
Paraphilias: ALL mainly in males (except masochism). Late-onset = think organic (dementia, dopamine agonists). Paraphilia ≠ disorder unless causing distress/harm.
Gender Dysphoria: Gender identity formed by age 3; 39% MZ concordance; atypical brain differentiation from prenatal sex hormones; management follows SOC guidelines (psychological assessment → counselling → real-life experience → hormones → surgery). NOT about making identity match assigned sex.
Assessment of SD: Define the problem, sexual Hx (morning erections, masturbation), PMHx, drug Hx, examination (vasculopathy, neuropathy, hormonal, genitals), investigations (hormones, TFT, prolactin).
Sensate Focus: graded touching tasks, ban on intercourse initially → reduces performance anxiety.
Vaginismus: phobic response → muscle spasm → gradual desensitisation with dilators.

High Yield Summary — Differential Diagnosis of Psychosexual Disorders

Sexual dysfunctions: Always exclude organic (DM #1, CVD), medication-induced (SSRIs #1), psychiatric (depression ~50% have SD), and relational causes before diagnosing primary sexual dysfunction.
Situational vs Generalised is the most important clinical distinction for sexual dysfunction — situational = likely psychogenic/relational; generalised = likely organic.
Paraphilias: Distinguish from OCD with sexual obsessions (ego-dystonic vs ego-syntonic), organic disinhibition (late-onset = always investigate), mania, substance use, and personality disorders.
Late-onset paraphilia = organic until proven otherwise (frontotemporal dementia, dopamine agonists, brain tumour).
Gender dysphoria: Distinguish from gender non-conformity (no distress), transvestic fetishism (arousal-driven), BDD (appearance-focused), psychosis (delusional), and normal childhood exploration.
Always assess comorbid psychiatric illness — mood and anxiety disorders are highly comorbid with all psychosexual disorders, and treating these may resolve or improve sexual symptoms.
Drug history is essential — SSRIs, antipsychotics, antihypertensives, dopamine agonists, and substances of abuse are all common culprits.

High Yield Summary — Diagnosis of Psychosexual Disorders

All DSM-5 sexual dysfunctions require: ≥ 6 months duration, clinically significant distress, not better explained by another disorder/substance/medical condition. Specify lifelong vs acquired, generalised vs situational.
Paraphilic disorders require TWO criteria: (A) recurrent intense atypical fantasies/urges/behaviours ≥ 6 months AND (B) distress/impairment OR involvement of non-consenting persons. Paraphilia without Criterion B is NOT a disorder.
Gender dysphoria in adults requires ≥ 2 of 6 features for ≥ 6 months + distress. In children, ≥ 6 of 8 features (higher threshold to avoid over-diagnosis). ICD-11 reclassified as "Gender Incongruence" outside of mental disorders.
Investigations for sexual dysfunction ^[2]: RFT, LFT, alcohol, TFT, pituitary hormones (prolactin), sex hormone profile, HbA1c, lipids. Specialist: NPT (psychogenic vs organic ED), penile Doppler (vascular ED).
NPT is the gold standard for distinguishing psychogenic from organic ED: normal NPT = intact neurovascular mechanism = psychogenic.
Morning erections preserved + situational dysfunction = psychogenic. This simple clinical observation often obviates expensive testing.
Late-onset paraphilia → MRI brain to exclude frontotemporal dementia or tumour.
Gender dysphoria diagnosis is clinical — investigations support pre-treatment workup, not diagnosis itself. Comprehensive psychiatric assessment to rule out comorbid Axis I disorders is essential.

High Yield Summary — Management of Psychosexual Disorders

Sexual dysfunctions: Treat underlying cause FIRST (organic, medication, psychiatric, relational). For the majority: self-help, advice, reassurance ^[2]. Sex therapy = partners together, communication, education, sensate focus (graded touching tasks, ban intercourse initially → ↓performance anxiety).
Specific exercises ^[2]: Female orgasmic disorder → fantasy/masturbation/vibrator. PE → squeeze technique, start-stop, quiet vagina. Vaginismus → graded dilator desensitisation.
ED pharmacotherapy ladder: PDE5i (first-line) → intracavernosal injection → vacuum device → penile prosthesis. PDE5i + nitrates = ABSOLUTE contraindication (fatal hypotension).
PE pharmacotherapy: SSRIs first-line (paroxetine most potent); dapoxetine (on-demand short-acting SSRI); topical anaesthetics adjunct.
SSRI-induced sexual dysfunction: Switch to bupropion/mirtazapine, ↓dose, drug holiday, add PDE5i for ED.
Paraphilias: Evidence is limited. Assessment (diagnosis with forensic implication + risk). Psychotherapy (covert sensitisation, aversion therapy, CBT). Pharmacotherapy escalating ladder: SSRIs → anti-androgens → GnRH agonists. Rehabilitation.
Gender dysphoria (SOC guidelines): Psychological assessment (rule out comorbidities) → counselling (NOT conversion therapy) → real-life experience ≥ 1 year → hormonal therapy (MtF: oestrogen + anti-androgen; FtM: testosterone) → gender-confirming surgery. 86% FtM and 71% MtF report improved QoL ^[2].
FtM testosterone effects: ↑clitoris size, ↑hair, deep voice, ↑muscle, cessation of menses. MtF oestrogen does NOT change voice — voice therapy needed separately.

High Yield Summary — Complications of Psychosexual Disorders

Sexual dysfunction creates a self-perpetuating vicious cycle: dysfunction → performance anxiety → sympathetic overdrive → more dysfunction → depression → SSRI → worsened dysfunction → SSRI non-compliance → depression relapse ^[2].
ED is a cardiovascular sentinel — untreated ED misses a 3–5 year window for CVD prevention.
Medication non-compliance from sexual side effects is one of the most dangerous and underappreciated complications — always proactively ask about sexual function when prescribing SSRIs, antihypertensives, and antipsychotics ^[2].
PDE5i + nitrates = catastrophic hypotension → absolute contraindication.
Priapism (sustained erection > 4 hours) from PDE5i or intracavernosal injection = urological emergency → aspiration + phenylephrine; delay causes ischaemic necrosis and permanent ED.
Paraphilias: Legal consequences dominate. Autoerotic asphyxiation in masochism → accidental death. Paedophilia → devastating lifelong trauma to child victims. GnRH agonists have an initial testosterone flare requiring anti-androgen cover.
Gender dysphoria: Suicidality is the most serious complication (40–45% lifetime suicide attempts). Oestrogen → VTE (most serious acute complication of MtF hormones). Testosterone → polycythaemia (most serious of FtM hormones). Phalloplasty has highest surgical complication rate (40–60%). 86% FtM, 71% MtF report improved QoL post-treatment ^[2].
Fertility preservation counselling must be offered before any irreversible hormonal or surgical treatment.

Psychosexual Disorders

1. Definition and Overview

2. Epidemiology

2.1 Sexual Dysfunctions

2.2 Paraphilias

2.3 Gender Dysphoria

3. Anatomy and Physiology of the Normal Sexual Response

3.1 Neuroanatomy of Sexual Function

3.2 The Four-Phase Sexual Response Cycle (Masters & Johnson / Kaplan)

4. Aetiology and Pathophysiology

4.1 Aetiology of Sexual Dysfunctions

4.1.1 Biological Factors

4.1.2 Psychological Factors [2]

4.1.3 Sociocultural Factors [2]

4.2 Aetiology of Paraphilias

4.3 Aetiology of Gender Dysphoria [2]

5. Classification

5.1 Classification of Sexual Dysfunctions

5.2 Classification of Paraphilias [2]

5.3 Classification of Gender Dysphoria [2]

6. Clinical Features

6.1 Sexual Dysfunctions — Symptoms and Signs

6.1.1 Disorders of Desire

6.1.2 Disorders of Excitement

6.1.3 Disorders of Orgasm

6.1.4 Sexual Pain Disorders

6.2 Paraphilias — Clinical Features [2]

6.3 Gender Dysphoria — Clinical Features [2]

7. Approach to Assessment

8. Key Specific Conditions — Additional Detail

8.1 Vaginismus — Treatment Detail [2]

8.2 Sensate Focus — Key Sex Therapy Technique [2]

9. Hong Kong–Specific Considerations

Active Recall - Psychosexual Disorders

References

1. Differential Diagnosis of Sexual Dysfunctions

1.1 Systematic Approach — The Differential Diagnosis Framework

1.2 Key Differential Diagnoses for Sexual Dysfunctions

1.3 Differentiating Specific Sexual Dysfunctions from Each Other

2. Differential Diagnosis of Paraphilias

3. Differential Diagnosis of Gender Dysphoria

4. Cross-Cutting Differential Considerations

5. Summary Differential Diagnosis Table

Active Recall - Differential Diagnosis of Psychosexual Disorders

1. Diagnostic Criteria

1.1 Sexual Dysfunctions — DSM-5-TR Criteria

1.1.1 Male Hypoactive Sexual Desire Disorder

1.1.2 Female Sexual Interest/Arousal Disorder

1.1.3 Erectile Disorder

1.1.4 Premature Ejaculation

1.1.5 Delayed Ejaculation

1.1.6 Female Orgasmic Disorder

1.1.7 Genitopelvic Pain/Penetration Disorder

1.1.8 Substance/Medication-Induced Sexual Dysfunction

1.2 Paraphilic Disorders — DSM-5-TR Criteria

1.3 Gender Dysphoria — DSM-5-TR Criteria [2]

In Adolescents and Adults

In Children

1.4 ICD-11 Classification Differences (Current WHO System)

2. Diagnostic Algorithm

2.1 Master Diagnostic Algorithm for Sexual Complaints

2.2 Algorithm for Distinguishing Psychogenic vs Organic Erectile Dysfunction

2.3 Algorithm for Gender Dysphoria Assessment [2]

3. Investigation Modalities

3.1 Investigations for Sexual Dysfunctions

3.1.1 Blood Investigations

3.1.2 Specialist Investigations

3.1.3 Psychological Assessment Tools

3.2 Investigations for Paraphilias

3.3 Investigations for Gender Dysphoria [2]

4. Interpretation Framework — Putting It All Together

Active Recall - Diagnostic Criteria and Investigations for Psychosexual Disorders

1. Master Management Algorithm — Sexual Dysfunctions

2. Management of Sexual Dysfunctions — Detailed

2.1 General Principles [2]

2.2 Sex Therapy — The Core Psychosexual Intervention

2.2.1 Sensate Focus [2]

2.2.2 Specific Exercises for Specific Dysfunctions [2]

2.3 Pharmacotherapy for Specific Sexual Dysfunctions

2.3.1 Erectile Disorder