GC170 Schizophrenia And Related Psychoses
Schizophrenia and related psychoses are a group of severe mental disorders characterized by disturbances in thought, perception, emotion, and behavior, including hallucinations, delusions, and disorganized thinking, often with impaired social and occupational functioning.
Schizophrenia & Related Psychoses
The Big Idea: Schizophrenia is a brain disease — not a "split personality" — that fundamentally disrupts a person's connection to reality. It is one of the leading causes of disability worldwide, typically striking in late adolescence/early adulthood, and follows a neurodevelopmental trajectory from premorbid vulnerability through prodrome to frank psychosis. Understanding its multi-dimensional symptomatology (positive, negative, disorganized, affective, motor, cognitive), neurobiological basis (dopamine hypothesis and beyond), aetiology (gene × environment), course (early intervention matters), and management (antipsychotics + psychosocial) is the key exam yield. [1]
Learning Objectives (inferred from lecture):
- Define psychosis and distinguish it from neurosis.
- Describe the epidemiology, burden, and course of schizophrenia.
- Explain Schneider's First Rank Symptoms (FRS) and their diagnostic utility.
- Classify symptom dimensions: positive, negative, disorganized, affective, motor, cognitive.
- Outline the neurodevelopmental and dopamine hypotheses.
- Identify genetic and environmental risk factors.
- Describe pharmacological (antipsychotics, clozapine) and non-pharmacological treatments.
- List prognostic factors and the rationale for early intervention.
- Differentiate schizophrenia from schizoaffective disorder, delusional disorder, brief psychotic disorder, and substance-induced psychosis.
How it fits: This lecture connects to the Psychopathology seminar (thought disorder, hallucinations, delusions), the Psychiatric History/MSE seminar (how to detect these symptoms clinically), the newer psych drugs lecture (GC 168 on antipsychotics), the ethics lecture (GC 173 on involuntary admission — relevant when patients lack insight), and the bipolar lecture (GC 163 — Kraepelian dichotomy). [1][2][3]
Psychosis = "out of reality." It is a syndrome characterized by: delusions, hallucinations, disorganization (thinking and/or behaviour), and lack of insight. [1]
| Concept | Psychosis | Neurosis |
|---|---|---|
| Reality testing | Impaired — patient cannot distinguish internal experiences from external reality | Preserved — patient knows their symptoms are abnormal |
| Insight | Typically absent | Typically present |
| Examples | Schizophrenia, delusional disorder, psychotic mania | Anxiety disorders, OCD, depression (without psychotic features) |
Why this matters: The psychosis vs. neurosis distinction is a foundational exam discriminator. A patient with OCD may have bizarre-sounding intrusive thoughts, but they have insight ("I know this is irrational"). A psychotic patient holds their delusion with conviction.
Schizophrenia is one type of psychotic disorder. Psychotic disorder is a disease of the brain. [1]
Chinese term in HK (since 2001): 思覺失調 — literally "disorder of thought and perception." [1]
Prevalence of psychotic disorders: ~2-3%. Lifetime risk of developing schizophrenia: ~1%. Median incidence rate: 15.2 per 100,000 per year. HK lifetime prevalence of psychotic disorders: 2.5%. [1]
| Parameter | Value | Why It Matters |
|---|---|---|
| Prevalence (all psychotic disorders) | ~2-3% | High-prevalence, low-incidence = chronic disease |
| Lifetime risk (schizophrenia) | ~1% | Common enough that every doctor will encounter it |
| Incidence | 15.2/100,000/yr | Varies widely (7.7–43) across regions |
| M:F ratio | 1.4:1 | Men more commonly affected |
| Age of onset | Late adolescence / early adulthood | Men earlier than women |
| Peak age (males) | 18–25 years | |
| Peak age (females) | Bimodal: 25–35 + perimenopause | Oestrogen may be protective [4] |
Incidence rates are elevated in: (1) migrants of ethnic minority (from developing to western countries, e.g. UK, Netherlands), and (2) individuals raised in urban vs. rural areas (urbanicity). [1]
Why these risk factors? The "social defeat hypothesis" / "stress-dopamine sensitization" model proposes that chronic social adversity (discrimination, isolation, minority status, urban stress) sensitizes the mesolimbic dopamine pathway, lowering the threshold for psychosis.
The conditions most frequently emerge in late adolescence or early adulthood, cause profound disruptions in individuals' personality development, social relationships, scholastic and vocational trajectories. Potentially chronic, remitting-relapse course, with significant functional impairment. [1]
3. Development & Course of Schizophrenia
Phases: Premorbid → Prodrome (ARMS/CHR) → First Psychotic Episode (FEP) → Longitudinal Course (fully recovered / residual deficits / no transition to psychosis from prodrome). [1]
- Childhood period before any psychiatric symptoms emerge.
- Some patients show subtle abnormalities: motor deficits, neurological soft signs, lower IQ, poor social functioning.
- These premorbid features support the neurodevelopmental hypothesis — the idea that schizophrenia is not purely degenerative but involves abnormal brain development from early life.
- Attenuated (sub-threshold) psychotic symptoms: vague suspiciousness, perceptual disturbances, social withdrawal, functional decline.
- Not all individuals in prodrome transition to psychosis (~30% do).
- This is the target of indicated prevention and early intervention programs.
- Full-blown psychotic symptoms meeting diagnostic criteria.
- Critical period = first 3–5 years after onset — outcomes during this window strongly predict long-term trajectory.
- Variable: some fully recover, some have relapsing-remitting course, some develop chronic residual deficits (predominantly negative symptoms and cognitive impairment).
Kraepelin (1896): "Dementia praecox" — classified based on progressive downhill course. Kraepelian dichotomy: dementia praecox vs. manic-depressive insanity (i.e. bipolar affective disorder). [1]
Bleuler (1911): Coined "Schizophrenia" (Greek = splitting of the mind). Fundamental symptoms: loosening of association, affect flattening, autism, ambivalence (the "4 As"). [1]
Why does this matter for exams? The Kraepelian dichotomy — schizophrenia (poor prognosis, thought disorder) vs. bipolar (episodic, affective, better prognosis) — remains the foundation of modern psychiatric classification, even though real patients often fall on a spectrum.
Bleuler's Classic Subtypes
| Subtype | Key Features | Prognosis |
|---|---|---|
| Paranoid | Prominent positive symptoms (delusions, hallucinations) | Best among subtypes |
| Hebephrenic (disorganized) | Younger onset, prominent thought disorder, incongruous affect | Poor |
| Catatonic | Motor signs: posturing, waxy flexibility, mutism | Variable |
| Simple | Lacks positive symptoms, gradual functional decline, prominent negative symptoms | Poor |
Subtype classification is no longer included in DSM-5. Catatonia is not specific to schizophrenia; it is currently a diagnostic specifier in DSM-5 (can occur in mood disorders, medical conditions, etc.). [1]
Exam Trap
Don't confuse "schizophrenia" with "split personality." The Greek etymology refers to a splitting of psychic functions (thought, emotion, behaviour become disconnected), NOT multiple personality disorder (now called Dissociative Identity Disorder).
5. Symptomatology — The Six Dimensions
Symptom dimensions in schizophrenia: (1) Positive symptoms, (2) Negative symptoms, (3) Disorganization, (4) Affective symptoms, (5) Motor signs (catatonia), (6) Cognitive impairment. [1]
The most common positive symptoms include delusion of reference and persecution, and auditory verbal hallucination (AVH). [1]
Delusions:
- Fixed, false beliefs held with unshakeable conviction despite contradictory evidence, not accounted for by cultural/religious background.
- Un-understandable (Jaspers, 1913) / Bizarreness — a key characteristic. [1]
- Types: persecutory (most common), referential (most common alongside persecutory), grandiose, nihilistic, somatic, erotomanic, jealous.
A belief that is firmly held (unshakeable) on inadequate ground. — This exact definition appeared in the 2023 Fourth Summative MCQ Q23. [5]
Hallucinations:
- False perceptions in the absence of a sensory stimulus, not controlled by will.
- Auditory hallucinations are the commonest modality in schizophrenia. [2]
- Visual hallucinations suggest organic brain pathology (e.g. delirium, substance use, DLB) — this is a key discriminator.
High Yield — Visual Hallucinations as Discriminator
The 2022 Fourth Summative MCQ Q26 asked: which feature indicates substance-induced psychosis rather than schizophrenia? Answer: Visual hallucinations. [6] In schizophrenia, auditory hallucinations dominate. Visual hallucinations should prompt consideration of organic/substance aetiology.
Kurt Schneider (1959): symptoms of "first rank of importance" — specific to schizophrenia and facilitating diagnostic assignment. [1]
| FRS Category | Description | Why It Matters |
|---|---|---|
| 3rd-person AVH (voices conversing) | Two or more voices discussing the patient | Specific to schizophrenia in Schneider's framework |
| Running commentary AVH | Voice narrating the patient's actions in real-time | |
| Thought echo | Voice repeating the patient's own thoughts aloud | |
| Thought alienation | Thought insertion, withdrawal, broadcasting | Patient feels thoughts are not their own / are being removed / are accessible to others |
| Passivity / Delusion of control | Feelings, actions, impulses experienced as made or influenced by external agents | "My hand was moved by aliens" |
| Delusional perception | Normal perception followed by a delusional interpretation with no logical connection | "I saw the traffic light turn red and knew the government was after me" |
| Somatic hallucination | Bodily sensations attributed to external agency |
Mnemonic (from Ryan Ho): SPECTRA — Somatic hallucination, Passivity, Echo of thoughts, Commentary, Thought alienation, Running commentary, Alien (delusional) perception. [4]
Literature showed that FRS are not specific to schizophrenia & with minimal prognostic predictive value. Nonetheless, FRS are still widely applied & emphasized in current classifications. [1]
Why do we still use FRS if they're not specific? Because (a) they remain central to ICD-10/11 diagnostic criteria for schizophrenia, (b) they are heavily tested in exams, and (c) when present, they strongly suggest schizophrenia over other psychotic disorders, even if they occasionally appear in mania or organic psychosis.
A core feature of schizophrenia. Key determinant of functional outcome. Unmet therapeutic need — NOT responsive to antipsychotic treatment. [1]
| Negative Symptom | Description | Clinical Observation |
|---|---|---|
| Affect flattening | Reduced affective response | Reduced facial expression, gesture, spontaneous movement, intonation, eye contact |
| Alogia | Poverty of speech | Brief, empty replies |
| Anhedonia | Reduced capacity to experience pleasure | "Nothing makes me happy anymore" |
| Avolition | Reduced motivation with reduced goal-directed behaviour | Can't get out of bed, doesn't initiate activities |
| Asociality | Reduced social drive with social withdrawal | Stays in room, avoids family and friends |
Mnemonic: The 5 A's of negative symptoms.
Why are negative symptoms so important? Because:
- They are the strongest predictor of long-term functional outcome (more than positive symptoms).
- They are resistant to current antipsychotic treatment — this is a major unmet need.
- They are often confused with depression or medication side effects (secondary negative symptoms from EPS, sedation, or depression must be excluded).
Primary vs Secondary Negative Symptoms
Before diagnosing primary negative symptoms, rule out: (1) Depression, (2) Antipsychotic side effects (sedation, EPS/akinesia), (3) Social deprivation/institutionalization, (4) Substance use. These cause "secondary" negative symptoms that may improve with targeted treatment.
- Abnormality in the form (not content) of thinking.
- Loosening of association (derailment, tangentiality, circumstantiality) is characteristic of schizophrenia. [2]
- Other features: word salad, neologism, over-inclusion, concrete thinking, knight's move thinking.
- Disorganized behaviour: unpredictable, bizarre, inappropriate actions.
- Depression and mania can co-occur with schizophrenia.
- Depressed mood is one of the strongest predictors of suicide in early-stage psychotic disorders. [1]
- Posturing, waxy flexibility, mutism, stupor, negativism, echolalia, echopraxia.
- Remember: catatonia is not specific to schizophrenia — it can occur in mood disorders, medical conditions (encephalitis, metabolic), and is a DSM-5 specifier.
A core feature in schizophrenia. Key determinant of functional outcome. Unmet therapeutic need — NOT responsive to antipsychotic treatment. [1]
| Cognitive Domain | Details |
|---|---|
| Sustained attention | Difficulty maintaining focus |
| Executive functions | Planning, set-shifting, inhibition control |
| Working memory | Holding/manipulating information in real-time |
| Verbal and visual memory | Immediate registration and recall |
| Processing speed | Slower information processing |
In general, 1-2 standard deviations below normal healthy controls. Healthy first-degree relatives also demonstrate deficits (albeit less severe). Impairment in social cognition is observed including deficits in Theory of Mind (ToM) and emotion recognition. [1]
Why do relatives show deficits? This supports the genetic basis — cognitive impairment is an endophenotype (an intermediate trait between genotype and clinical phenotype) that is heritable and present even in unaffected relatives.
6. Suicide & Mortality
Suicide is the single largest cause of premature death in schizophrenia. Lifetime risk: ~5.6% (from FEP cohorts). Risk is highest in the early stage, especially the first year after FEP. Suicide risk is 12× that of the general population. [1]
Depressed mood is one of the strongest predictors of suicide, and is frequently observed in the early stage of illness. [1]
Other risk factors for suicide in schizophrenia:
- Male sex, young age, early stage of illness
- Higher premorbid functioning (more insight into lost potential → hopelessness)
- Command hallucinations
- Previous suicide attempts
- Comorbid substance abuse
- Social isolation
Schizophrenia reduces lifespan by 10-15 years on average. All-cause SMR: 2-3. In HK: SMR 2.5, shortened life expectancy 8-10 years. [1]
Possible reasons for elevated natural deaths: (1) Sedentary lifestyle, lack of exercise, poor nutrition; (2) Cigarette smoking, substance/alcohol abuse; (3) Metabolic syndrome (obesity, DM, hyperlipidaemia) — partly from second-generation antipsychotics; (4) ?Inherent disease process involving accelerated aging. [1]
Clinical implication: Every patient with schizophrenia needs regular metabolic monitoring (weight, fasting glucose, lipid profile, BP) — especially those on second-generation antipsychotics like olanzapine and clozapine.
7. Aetiology
High degree of heritability: ~80% contributed by genetic cause. Polygenic: multiple genes with small effects. Many candidate genes related to dopamine, glutamate, synaptic functions, and immune mechanisms. [1]
| Relationship | Risk |
|---|---|
| General population | ~1% |
| First-degree relative | 10-15% |
| DZ twin | ~17% |
| MZ twin | ~50% |
| Both parents affected | ~46% |
Rare copy number variants (CNV) with larger effect: e.g. Chromosome 22q11.2 deletion syndrome (DiGeorge / VCFS) — associated with 20-30 fold increase in risk. [1]
Why only 50% concordance in MZ twins? Because genetics confers vulnerability, not certainty. Environmental factors must interact with genetic predisposition (gene × environment interaction).
Distal (prenatal/perinatal): obstetric complications, winter birth, maternal infections (influenza, toxoplasmosis), advanced paternal age at conception. [1]
Proximal social risk factors: substance abuse (cannabis), migration (ethnic minority), urbanicity (urban upbringing). [1]
Why cannabis? Cannabis (especially high-potency THC) acts on the endocannabinoid system which modulates dopamine release. Adolescent cannabis use during the critical period of brain maturation increases risk of psychosis in genetically vulnerable individuals.
Why advanced paternal age? Spermatogonia accumulate de novo mutations with each cell division over a man's lifetime. Older fathers have more mutations, including in genes relevant to neurodevelopment.
Gene × environment interactions. [1]
The stress-vulnerability model: A person's genetic loading determines their threshold for psychosis; environmental stressors push them over that threshold. Some people have very low thresholds (high genetic risk) and need minimal stress; others have high thresholds and may never develop psychosis even with significant adversity.
8. Neurobiology
Increased pre-synaptic dopamine synthesis in the striatum → hyperdopaminergic transmission → manifestations of psychosis. [1]
The four dopamine pathways — absolutely essential for exams:
| Pathway | Function | Clinical Relevance |
|---|---|---|
| Mesolimbic | Reward, motivation | Hyperactivity → positive symptoms (delusions, hallucinations). Target of antipsychotic action. |
| Mesocortical | Cognition, executive function, motivation | Hypoactivity → negative symptoms & cognitive impairment. Antipsychotics may worsen this. |
| Nigrostriatal | Motor control | Blockade → EPS (parkinsonism, dystonia, akathisia, tardive dyskinesia) |
| Tuberoinfundibular | Inhibits prolactin release | Blockade → hyperprolactinaemia (galactorrhoea, amenorrhoea, sexual dysfunction, osteoporosis) |
Why does blocking D2 in the mesolimbic pathway help positive symptoms but worsen negative/cognitive symptoms? Because current antipsychotics are non-selective D2 blockers — they block D2 everywhere. In the mesolimbic pathway, this reduces the dopamine excess causing psychosis. But in the mesocortical pathway, where dopamine is already low, further blockade worsens negative and cognitive symptoms.
Other neurotransmitters: glutamate (NMDA hypofunction), GABA. Excess glutamate neurotransmission → neurotoxicity / may lead to hyperdopaminergia. [1]
The glutamate-NMDA hypothesis: NMDA receptor hypofunction (e.g. from PCP or ketamine, which are NMDA antagonists) produces psychosis-like symptoms including both positive AND negative symptoms — better mimicking schizophrenia than pure dopaminergic agents. This suggests glutamate dysfunction is upstream of dopamine abnormalities.
Absence of gliosis + lack of evidence of neuronal loss + reduction in synapse-rich neuropil → argues AGAINST a neurodegeneration hypothesis. [1]
Translation: If schizophrenia were a neurodegenerative disease (like Alzheimer's), you'd expect to see gliosis (scarring from dead neurons) and neuronal loss. The absence of these, combined with reduced synaptic density (neuropil), supports the neurodevelopmental hypothesis — the problem is aberrant brain development (abnormal synaptic pruning, connectivity), not progressive neuronal death.
Reduced whole brain volume / gray matter (GM) volume — especially temporal lobe (hippocampus, amygdala, STG), prefrontal cortex, thalamus, anterior cingulate. Increased ventricular volume. Reduced cortical thickness. Altered white matter integrity (DTI). Altered functional connectivity (fMRI). Evidence of progressive structural brain changes across illness course in a subgroup. [1]
Mechanism of action: D2 receptor antagonist (striatum). Excessive D2 blockade (> 70-80% of striatal D2 receptors) → motor side effects. [1]
The therapeutic window: You need ~60-70% D2 occupancy for antipsychotic effect, but > 70-80% causes EPS. This narrow window explains why dose optimization matters.
First-generation (typical) vs. Second-generation (atypical) antipsychotics:
| Feature | First-Generation (FGA) | Second-Generation (SGA) |
|---|---|---|
| Examples | Haloperidol, chlorpromazine | Risperidone, olanzapine, quetiapine, aripiprazole, clozapine |
| Mechanism | Primarily D2 blockade | D2 + 5-HT2A blockade (broader receptor profile) |
| EPS risk | Higher | Lower (except risperidone at high doses) |
| Metabolic effects | Lower | Higher (especially olanzapine, clozapine) |
| Prolactin elevation | High (especially haloperidol) | Variable (risperidone high; quetiapine, aripiprazole low) |
High Yield — Antipsychotics & Hyperprolactinaemia
Antipsychotics (especially risperidone, haloperidol) block D2 receptors in the tuberoinfundibular pathway, removing tonic dopamine inhibition on prolactin release → hyperprolactinaemia → galactorrhoea, amenorrhoea, gynecomastia, sexual dysfunction, osteoporosis. This is commonly tested and connects to the endocrine block (pituitary tumours lecture). [7]
Tardive dyskinesia — a Type C adverse drug reaction (from long-term use), characterized by involuntary, repetitive movements (lip smacking, tongue protrusion, chewing). Classic exam point from the Clinical Pharmacology lecture. [8]
Antipsychotic medication is the mainstay treatment. Effective in treating positive psychotic symptoms. > 80% of FEP patients respond to antipsychotic treatment in the first psychotic episode. [1]
High risk of relapse. Major risk factor of relapse: non-adherence to medication. At least 1-2 year maintenance antipsychotic treatment following positive symptom remission is recommended for FEP (also depends on individual case). [1]
Treatment-Resistant Schizophrenia (TRS)
TRS defined as: persistent, prominent positive psychotic symptoms despite at least 2 trials of different types of antipsychotic medications with adequate dose and adequate duration (6-8 weeks each). Indication for clozapine initiation. [1]
Why clozapine specifically? Clozapine is the ONLY antipsychotic with proven superiority in treatment-resistant schizophrenia. Its unique receptor profile (relatively low D2 affinity, high D4, 5-HT2A, muscarinic, histaminergic affinity) may explain this.
Clozapine caveats (high yield for exams):
- Agranulocytosis risk (~1%) → mandatory regular blood monitoring (weekly for first 18 weeks, then monthly)
- Metabolic syndrome (weight gain, DM, dyslipidaemia)
- Myocarditis/cardiomyopathy (especially in first month)
- Seizures (dose-related)
- Sedation, hypersalivation (drooling), constipation (can progress to ileus)
- Despite these risks, clozapine is actually associated with reduced suicide risk in schizophrenia
CBT: for residual positive psychotic symptoms (e.g. residual AH), and comorbid depressive and anxiety symptoms. [1]
Treatment compliance therapy. Cognitive remediation. Occupational rehabilitation / vocational support & training / social skills training. Community case-management approach. Family intervention (expressed emotions / EE, caregiver stress & burden, psychoeducation, support). [1]
ECT for catatonia / treatment-resistant schizophrenia. [1]
| Intervention | Target | Rationale |
|---|---|---|
| CBT | Residual hallucinations, delusions; comorbid depression/anxiety | Helps patients reappraise psychotic experiences; reduces distress |
| Compliance therapy | Medication adherence | Non-adherence is the #1 risk factor for relapse |
| Cognitive remediation | Cognitive impairment | Trains attention, memory, executive function |
| Occupational/vocational | Functional recovery | Addresses disability — the core burden of the disease |
| Family intervention | High expressed emotion (EE) | High EE (critical, hostile, over-involved family) predicts relapse |
| ECT | Catatonia, treatment-resistant cases | Rapid response in catatonia; adjunct in refractory psychosis |
Poor prognostic factors: poor premorbid adjustment, early/young age of onset, insidious onset, male gender, hebephrenic subtype, prominent negative symptoms, severe cognitive impairment, prolonged DUP, comorbid substance abuse, high expressed emotions (EE) of caregivers, poor initial treatment response. [1]
| Good Prognosis | Poor Prognosis |
|---|---|
| Late onset | Early / young onset |
| Female | Male |
| Acute onset | Insidious onset |
| Good premorbid adjustment | Poor premorbid adjustment |
| Prominent affective symptoms | Prominent negative symptoms |
| Paranoid subtype | Hebephrenic subtype |
| Short DUP | Prolonged DUP |
| Good treatment response | Poor initial response |
| Family support, low EE | High EE, substance abuse |
| Preserved cognition | Severe cognitive impairment |
EI model has been the major focus in mental health service development in the past two decades. Rationale: (1) Early detection: shorten treatment delay (DUP). (2) Phase-specific intervention: optimal treatment in the critical period (3-5 years after illness onset). [1]
Both overseas and local research demonstrated effectiveness of EI over standard care. Hong Kong: EASY program (Early Assessment Service for Young people with psychosis). Detection and intervention for at-risk mental state (ARMS) for psychosis = indicated prevention. [1]
Why does DUP matter? Longer DUP is associated with:
- Poorer treatment response
- More severe symptoms at presentation
- Worse long-term functional outcomes
- Greater brain structural changes
EASY Program (HK-specific — exam relevant): A Hong Kong-based early intervention program for psychosis targeting young people aged 15–64 (initially 15–25). Provides multidisciplinary care including psychiatry, clinical psychology, nursing, social work, and occupational therapy during the critical period.
14. Related Psychotic Disorders
Schizophrenia-spectrum: schizophrenia, schizoaffective disorder, schizotypal personality disorder. [1]
Schizoaffective: concurrent schizophrenic and mood symptoms are equally prominent (fulfilling a major mood episode e.g. manic or depressive episode). [1]
Key distinction from schizophrenia: In schizophrenia, mood symptoms may occur but are not the dominant feature. In schizoaffective disorder, a full mood episode (mania or major depression) co-exists with schizophrenic symptoms, and psychotic symptoms persist for ≥2 weeks even WITHOUT mood symptoms.
Acute onset / complete remission / brief period (1-3 months, depends on criteria). Polymorphic features (~cycloid psychosis): rapidly changing clinical pictures, prominent fluctuating mood state, perplexity. [1]
Key points: Good prognosis, full recovery expected. If symptoms persist > 1 month (DSM-5) or > 3 months (ICD-10), reconsider diagnosis.
Systematized, likely single-theme delusion, non-bizarre in nature (classic definition). No or non-prominent hallucination. Minimal negative symptoms, reported of having better functioning. Over-represented by women and adult-onset. Relatively rare. [1]
| Feature | Schizophrenia | Delusional Disorder |
|---|---|---|
| Delusions | Bizarre, fragmented, multiple themes | Non-bizarre, systematized, single-theme |
| Hallucinations | Prominent (especially AVH) | Absent or minimal |
| Negative symptoms | Often present | Minimal |
| Functioning | Often impaired | Relatively preserved |
| Age of onset | Young adults | Later (median ~46 years) [4] |
Delusional disorder themes (from Ryan Ho notes): Persecutory (commonest), erotomania, jealous, somatic, grandiose. [4]
This is a critical clinical and exam discriminator:
| Feature | Substance-Induced Psychosis | Primary Psychosis (Schizophrenia) |
|---|---|---|
| Visual hallucinations | More common | Less common (auditory dominates) |
| Temporal relationship | Symptoms during/shortly after substance use | No clear temporal link |
| Duration | Usually resolves with abstinence | Persists |
| FRS | Less common | More common |
| Disorganization | Can occur | Can occur |
From 2022 Fourth Summative MCQ Q26: Visual hallucinations indicate substance-induced psychosis rather than schizophrenia. [6]
While the lecture focuses on clinical concepts rather than listing criteria verbatim, knowledge of DSM-5 criteria is essential:
| Criterion | Requirement |
|---|---|
| A | ≥2 of: (1) Delusions, (2) Hallucinations, (3) Disorganized speech, (4) Grossly disorganized or catatonic behaviour, (5) Negative symptoms. At least one must be (1), (2), or (3). |
| B | Social/occupational dysfunction |
| C | Duration ≥6 months (including prodrome/residual); ≥1 month of Criterion A symptoms |
| D | Schizoaffective and mood disorders excluded |
| E | Not due to substance or medical condition |
| F | If autism/communication disorder history, schizophrenia only if prominent delusions/hallucinations present for ≥1 month |
Exam Intelligence
| Trap | Correct Approach |
|---|---|
| Confusing schizophrenia with "split personality" | Schizophrenia = splitting of psychic functions, NOT dissociative identity disorder |
| Assuming FRS are pathognomonic for schizophrenia | FRS are not specific to schizophrenia — can occur in mania, organic psychosis [1] |
| Treating negative symptoms with higher-dose antipsychotics | Negative symptoms are NOT responsive to antipsychotics — rule out secondary causes first [1] |
| Assuming all antipsychotics are equal in TRS | Only clozapine is indicated for TRS after 2 failed adequate trials [1] |
| Visual hallucinations = schizophrenia | Visual hallucinations suggest organic/substance-induced cause [6] |
| Forgetting metabolic monitoring on SGAs | SGAs (especially olanzapine, clozapine) cause metabolic syndrome → monitor weight, glucose, lipids |
| Delusion of guilt in a depressed patient = schizophrenia | Delusion of guilt is mood-congruent in depression, not schizophrenia (2020 MCQ Q93: answer is A) [9] |
| "Pseudodementia" = schizophrenia | Pseudodementia = depressive disorder mimicking dementia, NOT schizophrenia (2020 MCQ Q24: answer is A) [9] |
- Drug-related questions commonly tested and commonly failed [10]
- Know: antipsychotics (typical vs atypical, side effects, clozapine monitoring), antidepressants, mood stabilizers, benzodiazepines
- Mental Health Ordinance: Form 1 (family), Form 2 (doctor), Form 3 (magistrate) — involuntary admission [10]
2023 Fourth Summative MCQ Q23 [5]:
"Delusion is one of the important symptoms in schizophrenia. Which of the following is the characteristic of delusion?"
- A. A belief that is firmly held (unshakeable) on inadequate ground. ✅
- B. It frequently exists in patients with mood disorder.
- C. It usually resolves when factual proof is presented.
- D. Patients with delusion usually have good insight.
Answer: A. A delusion is by definition firmly held, not amenable to counter-argument (eliminates C), and patients with delusions by definition lack insight into the false nature of the belief (eliminates D). While delusions CAN occur in mood disorders (B), this is not the defining characteristic — B is a true statement but not the best answer for "characteristic of delusion."
2022 Fourth Summative MCQ Q26 [6]:
"A 23-year-old university student presented to A&E with auditory hallucinations, visual hallucinations, persecutory delusion, passivity experience and disorganised speech. He had a recent history of amphetamine abuse. Which of the following clinical features indicates substance-induced psychosis, rather than schizophrenia, is the MOST LIKELY diagnosis?"
- A. Disorganised speech
- B. Passivity experience
- C. Persecutory delusion
- D. Visual hallucinations ✅
Answer: D. Visual hallucinations are more suggestive of organic/substance-induced psychosis. Passivity experience (B) and disorganized speech (A) are more characteristic of schizophrenia. Persecutory delusions (C) are common in both conditions.
2020 Fourth Summative MCQ Q93 [9]:
"A 35-year-old man complained of a low mood, lack of motivation, early morning wakening and hopelessness about the future. His work performance has deteriorated significantly and was therefore laid off by his company. He was socially withdrawn and stayed at home most of the time. Which of the following is the MOST LIKELY psychopathology that he may have?"
- A. Delusion of Guilt ✅
- B. Delusion of Love
- C. Formal thought disorder
- D. Grandiose delusion
Answer: A. This is a depressive presentation (low mood, early morning wakening, hopelessness, functional decline). The most likely associated psychopathology is mood-congruent delusion of guilt (he may believe he deserves his suffering, that he is worthless). Formal thought disorder (C) is more characteristic of schizophrenia. Grandiose delusion (D) is seen in mania. This question tests the ability to distinguish schizophrenic psychopathology from depressive psychopathology.
2020 Fourth Summative MCQ Q24 [9]:
"Which of the following psychiatric conditions can mimic dementia and is known as 'pseudodementia' in a geriatric patient?"
- A. Depressive disorder ✅
- B. Manic episode
- C. Post-traumatic stress disorder
- D. Schizophrenia
Answer: A. Pseudodementia = depressive pseudodementia. Severe depression in elderly can mimic cognitive decline (poor concentration, psychomotor retardation, apathy). Key discriminator from true dementia: in pseudodementia, patients often complain about their memory (vs. true dementia where patients minimize deficits), and cognitive deficits improve with antidepressant treatment.
2024 Fourth Summative MCQ Q14 [11]:
"A 36-year-old, gravida 1 para 1, delivered her baby 4 weeks ago... low mood, guilt about baby care, fleeting suicidal thoughts... What is the MOST LIKELY diagnosis?"
- A. Normal reaction to physical complaint of wound pain
- B. Postpartum depression ✅
- C. Puerperal blues
- D. Puerperal psychosis
Answer: B. Puerperal blues occur within first 2 weeks postpartum and are self-limiting (not at 4 weeks with suicidal thoughts). Puerperal psychosis typically presents with confusion, delusions, hallucinations (not described here). The presence of low mood, guilt, and suicidal ideation at 4 weeks = postpartum depression. This tests differentiation from puerperal psychosis (which IS a psychotic disorder and relates to this lecture).
High Yield Summary
Schizophrenia is a brain disease (not split personality) with ~1% lifetime risk, M:F 1.4:1, onset in late adolescence/early adulthood.
Six symptom dimensions: Positive (delusions, hallucinations — most respond to antipsychotics), Negative (5 A's — NOT responsive to antipsychotics, key for functional outcome), Disorganization, Affective, Motor (catatonia), Cognitive (1-2 SD below normal).
Schneider's FRS (thought echo, 3rd-person AVH, running commentary, thought alienation, passivity, delusional perception, somatic hallucination) — still used in classification but NOT specific to schizophrenia.
Aetiology: ~80% heritable, polygenic + rare CNVs (22q11.2 = 20-30× risk). Environmental: cannabis, urbanicity, migration, obstetric complications. Gene × environment interaction via stress-vulnerability model.
Dopamine hypothesis: Mesolimbic hyperactivity → positive symptoms; Mesocortical hypoactivity → negative/cognitive symptoms. Four dopamine pathways explain both therapeutic effects and side effects of antipsychotics.
Treatment: Antipsychotics (D2 blockade) — > 80% respond in FEP. Maintenance 1-2 years minimum. Non-adherence = #1 relapse risk. TRS (failed 2 adequate trials) → clozapine. Non-pharmacological: CBT, family intervention (EE), vocational rehab, ECT for catatonia.
Prognosis: Poor = male, young onset, insidious onset, negative symptoms, cognitive impairment, long DUP, high EE, substance abuse. Early intervention (EASY program in HK) shortens DUP and improves outcomes.
Suicide: 5.6% lifetime risk, highest in first year of FEP, 12× general population. Depression is the strongest predictor.
Exam discriminators: Visual hallucinations → think organic/substance-induced, not schizophrenia. Negative symptoms ≠ depression (rule out secondary causes). Clozapine = only drug for TRS. FRS are not pathognomonic.
Active Recall - Schizophrenia & Related Psychoses
[1] Lecture slides: GC 170. Schizophrenia and related psychoses.pdf [2] Lecture slides: Seminar 1 - Psychiatric History Taking and Mental State Examination - Dr SE Chua_20250825.pdf (p.33) [3] Lecture slides: Seminar 2 - Psychopathology - Dr Simon SY Lui_1_9_2025.pdf (p.26) [4] Senior notes: Ryan Ho Psychiatry.pdf (pp.129, 134) [5] Past papers: 2023 Fourth Summative MCQ.pdf (Q23) [6] Past papers: 2022 Fourth Summative MCQ.pdf (Q26) [7] Senior notes: Block A - I keep on bumping into people on my side_ pituitary tumours; hypopituitarism.pdf (p.9) [8] Senior notes: Block A - Introduction to Clinical pharmacology (II) (Drug Interactions, adverse drug reactions).pdf (p.1) [9] Past papers: 2020 Fourth Summative Assessment MCQ paper.pdf (Q24, Q93) [10] AOS material: AOS - Psych.md [11] Past papers: 2024 Fourth Summative MCQ.pdf (Q14)
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