Psychotic Disorders (F2)

Schizophrenia And Related Disorders

Schizophrenia and related disorders are a group of chronic psychiatric conditions characterized by disturbances in thought, perception, affect, and behavior, including symptoms such as delusions, hallucinations, disorganized thinking, and negative symptoms.

2. Epidemiology

3. Anatomy and Functional Neuroanatomy

Understanding schizophrenia requires understanding the dopamine pathways and the key brain regions affected.

4. Aetiology

Schizophrenia follows a multifactorial, gene–environment interaction model. Think of it as a stress-vulnerability framework: genes load the gun, environment pulls the trigger.

4.2 Environmental Factors

4.3 Neurobiology / Pathophysiology

6. Classification

7. Symptom Dimensions of Schizophrenia

Modern conceptualisation of schizophrenia moves away from simple "positive vs negative" to six symptom dimensions [2]:

7.1 Positive Symptoms — "Reality Distortions"

These represent an excess or distortion of normal brain functions. They are driven by hyperdopaminergic transmission in the mesolimbic pathway [1].

7.3 Disorganisation Symptoms — "Disorganised Thoughts and Behaviour"

These represent disrupted integration of thought and behaviour — the "split" in schizophrenia.

When a patient presents with psychotic symptoms (delusions, hallucinations, disorganised thinking/behaviour), the critical task is NOT to immediately label it "schizophrenia." Psychosis is a syndrome — a final common pathway — and the differential is broad. The hierarchy of psychiatric diagnosis dictates that you must rule out causes from the top of the pyramid (organic → substance → psychotic → mood → anxiety → personality) before settling on a diagnosis lower down [2].

Why does the hierarchy matter? Because treating the higher-order disorder (e.g., delirium from a UTI, or substance-induced psychosis from methamphetamine) often resolves the psychosis entirely. Missing an organic cause and treating with antipsychotics alone is a serious — and potentially lethal — error.

First Principle: Psychosis ≠ Schizophrenia

Psychosis is a syndrome (loss of contact with reality) that can be caused by many disorders. Schizophrenia is just ONE cause. Always exclude organic, substance-related, and mood-related causes first. The hierarchy is: Organic > Substance > Psychotic disorders > Mood disorders > Anxiety > Personality [2].


Category 1: Other Non-Affective Psychotic Disorders (Schizophrenia-Spectrum)

Schizophrenia-spectrum includes schizophrenia, schizoaffective disorder, schizotypal personality disorder [1].

Category 2: Mood Disorders with Psychotic Features

This is one of the most critical differentials — and one of the most commonly missed.

Category 3: Other Psychiatric Disorders that May Mimic Psychosis

This is the category you must not miss — organic psychosis can be life-threatening if the underlying cause is untreated.

References

[1] Lecture slides: GC 170. Schizophrenia and related psychoses.pdf (pp. 22) [2] Senior notes: ryanho-psych.md (sections 6.1, 6.2, pp. 123–124, 128, 132–133, 143, 165) [3] Lecture slides: GC 163. I am a superman Bipolar disorder.pdf (pp. 10, 12)

6. Investigations in First-Episode Psychosis

Remember: investigations in psychosis are not to confirm schizophrenia but to exclude secondary causes. A first-episode psychosis (FEP) should be treated as "guilty until proven innocent" — assume an organic cause until you've ruled it out.

References

[1] Lecture slides: GC 170. Schizophrenia and related psychoses.pdf (pp. 7, 8, 9, 11, 22) [2] Senior notes: ryanho-psych.md (sections 6.1, 6.2, pp. 4, 33, 124–125, 128–135) [4] Senior notes: ryanho-psych.md (section on ICD-10 vs DSM-5 comparison, pp. 6–7)

2. Pharmacological Treatment

3. Non-Pharmacological Treatment

Non-pharmacological treatments — usually as an adjunct to medications, aiming to [1][2]:

  • Increase interpersonal and social functioning, especially promotion of independent living in community
  • Attenuate symptomatic severity and associated comorbidities
  • Improve treatment compliance

References

[1] Lecture slides: GC 170. Schizophrenia and related psychoses.pdf (pp. 23, 24) [2] Senior notes: ryanho-psych.md (sections 6.2C, 3.1.2, 3.2, 3.3, pp. 45, 65–71, 135–138)

Complications of schizophrenia can be broadly divided into those arising from the disease itself, those arising from its treatment (iatrogenic), and those arising from the interaction between disease, treatment, and social context. Understanding these complications from first principles — connecting each back to pathophysiology or pharmacology — is essential.


1. Complications of the Disease Itself

2. Complications of Treatment (Iatrogenic)

2A. Antipsychotic Side Effects

These are among the most important complications to know — they directly affect adherence, morbidity, and mortality.

3. Complications from the Interaction of Disease, Treatment, and Social Context

References

[1] Lecture slides: GC 170. Schizophrenia and related psychoses.pdf (pp. 3, 4, 11, 12, 13, 23) [2] Senior notes: ryanho-psych.md (sections 6.2, pp. 128–131, 135–138) [5] Lecture slides: GC 161. Alcohol and the Brain From Psychiatric to Neuropsychiatric Perspectives.pdf (p. 44)

High Yield Summary

Definition: Schizophrenia is a chronic neurodevelopmental psychotic disorder characterised by positive symptoms (hallucinations, delusions), negative symptoms (5 A's), disorganisation, cognitive impairment, motor symptoms, and affective disturbance.

Epidemiology: Lifetime risk ~1%; prevalence of all psychotic disorders ~2–3%; M:F = 1.4:1; onset late adolescence/early adulthood; men earlier onset. HK prevalence 2.5%. Incidence varies with urbanicity and migration.

Aetiology — Stress-Vulnerability Model:

  • Genetics (80% heritability): Polygenic (dopamine, glutamate, synaptic, immune genes); 22q11.2 deletion → 20–30× risk; MZ concordance ~50%
  • Environment: Prenatal (obstetric complications, winter birth, infections, paternal age) + Proximal (cannabis, urbanicity, migration — social defeat hypothesis)
  • Gene × environment interaction

Pathophysiology:

  • Dopamine hypothesis: Mesolimbic hyper → positive symptoms; Mesocortical hypo → negative/cognitive symptoms
  • Glutamate: NMDA hypofunction → excess glutamate → hyperdopaminergia + neurotoxicity
  • GABA: Reduced GAD → disinhibition
  • Neuropathology: Reduced neuropil, NO gliosis → neurodevelopmental NOT neurodegenerative
  • Structural: Reduced GM (temporal, PFC, thalamus, anterior cingulate), increased ventricles, cortical thinning, white matter disconnectivity

Schneider's First Rank Symptoms (SPECTRA): Somatic passivity, Passivity of action/impulse, Echo of thoughts, Commentary/3rd person AVH, Thought insertion/withdrawal/broadcasting, Referential/delusional perception, Audible thoughts

Negative symptoms (5 A's): Avolition, Alogia, Anhedonia, Asociality, Affective flattening

Course: Premorbid → Prodromal (ARMS/CHR) → First Episode Psychosis → Variable longitudinal course (full recovery / residual deficits / chronic)

Delusional disorder: Non-bizarre, systematised, single-themed delusion ≥1 month; preserved functioning; no/minimal hallucinations or negative symptoms; lifetime risk 0.05–0.1%; median onset 46y

High Yield Summary

Approach to psychotic symptoms — always use the diagnostic hierarchy:

  1. Rule out organic/medical causes first — especially delirium (visual hallucinations, fluctuating consciousness, disorientation), anti-NMDA receptor encephalitis, and metabolic/endocrine conditions
  2. Rule out substance-induced psychosis — temporal relationship to substance use; urine tox screen; should remit after substance clears
  3. Distinguish from mood disorders with psychotic features — is psychosis occurring ONLY during mood episodes (mood disorder) or also independently (schizoaffective/schizophrenia)?
  4. Differentiate among psychotic disorders by duration — brief psychotic disorder ( < 1 month) → schizophreniform (1–6 months) → schizophrenia ( > 6 months)
  5. Delusional disorder — isolated, non-bizarre, encapsulated delusion; preserved functioning; no/minimal hallucinations or negative symptoms
  6. Schizotypal PD — attenuated psychotic-like features that are trait-like and enduring; never meets full criteria for schizophrenia

Classic exam pitfalls:

  • Manic psychosis misdiagnosed as schizophrenia (look for elevated mood, decreased need for sleep, grandiosity, pressured speech, episodic course)
  • Visual hallucinations should prompt organic work-up (delirium, Lewy body dementia, substance-induced)
  • Anti-NMDA receptor encephalitis in young women with new-onset psychosis + catatonia + seizures
  • Cannabis/methamphetamine-induced psychosis in Hong Kong context

High Yield Summary

Diagnosis of schizophrenia is CLINICAL — investigations exclude secondary causes, not confirm schizophrenia.

DSM-5 Criteria (memorise):

  • A: ≥2 of delusions, hallucinations, disorganised speech, disorganised/catatonic behaviour, negative symptoms; at least one must be delusions, hallucinations, or disorganised speech; present for significant portion of ≥1 month
  • B: Functional decline
  • C: ≥6 months total duration (including prodromal/residual)
  • D: Not schizoaffective or mood disorder with psychotic features
  • E: Not substance/medical condition
  • F: ASD clause

Key ICD-10 vs DSM-5 difference: ICD-10 requires 1 month; DSM-5 requires 6 months. ICD-10 retains subtypes; DSM-5 uses course specifiers.

Duration continuum: Brief psychotic disorder ( < 1 month) → Schizophreniform (1–6 months) → Schizophrenia ( ≥ 6 months)

Schizoaffective key criterion: Psychosis for ≥2 weeks WITHOUT mood episode

Mandatory FEP investigations: FBC, U&E, LFTs, TFTs, Ca²⁺, B12/folate, glucose, lipids, syphilis serology, ESR/CRP, urine drug screen, ECG. CT/MRI brain recommended for all FEP.

Cognitive impairment: Core feature, 1–2 SD below normal, strongest predictor of functional outcome, NOT responsive to antipsychotics — an unmet therapeutic need.

High Yield Summary

Pharmacological Treatment:

  • Antipsychotics are the mainstay; D2 receptor antagonism in the mesolimbic pathway reduces positive symptoms
  • 80% of FEP patients respond; 70–80% D2 occupancy needed; excessive blockade → EPS

  • Maintenance: ≥1–2 years after FEP; non-adherence is the major relapse risk factor → consider depot formulations
  • TRS definition: persistent positive symptoms despite 2 adequate antipsychotic trials (≥1 atypical, each 6–8 weeks, adequate dose)
  • Clozapine is the ONLY drug with proven superiority in TRS (~30% response rate); also reduces suicidality and aggression
  • Clozapine monitoring: neutrophil count weekly × 18 weeks → fortnightly to 1 year → monthly thereafter
  • Clozapine serious side effects: agranulocytosis, metabolic syndrome, seizures, myocarditis, constipation/ileus, PE
  • If clozapine fails: add another antipsychotic, ECT augmentation, or lamotrigine augmentation

Non-Pharmacological Treatment:

  • CBT for residual positive symptoms and comorbid depression/anxiety
  • Family therapy to reduce expressed emotions and caregiver burden
  • Cognitive remediation for cognitive impairment (unmet therapeutic need — not responsive to antipsychotics)
  • Compliance therapy, vocational rehabilitation, social skills training, community case management
  • Early intervention (EASY in HK): intensive support for first 3 years of psychosis → reduced suicide, hospitalisation, and default rates
  • ECT: reserved for catatonia, severe comorbid depression, and treatment-resistant cases

Prognosis: Chronic, heterogeneous; ~30% TRS, ~20% sustained remission, ~10% suicide, > 50% poor outcome. Poor prognostic factors include male sex, early onset, insidious onset, prolonged DUP, prominent negative symptoms, poor premorbid adjustment, substance abuse, and high EE.

High Yield Summary

Suicide: Single largest cause of premature death. Lifetime risk 5.6%. Highest in first year after FEP. Depressed mood is the strongest predictor. Paradoxically, better insight may increase risk.

Excess Mortality: Lifespan reduced 10–15 years (SMR 2.5 in HK). Majority from natural causes, especially cardiovascular disease. Driven by lifestyle, smoking, substance abuse, metabolic syndrome from SGAs, and possibly inherent accelerated aging.

Metabolic Syndrome: The most clinically significant long-term treatment complication. Olanzapine and clozapine are worst offenders. Mandatory baseline and regular metabolic monitoring for all patients on antipsychotics.

EPS: Acute dystonia (hours–days), akathisia (days–weeks), parkinsonism (weeks–months), tardive dyskinesia (months–years, potentially irreversible). All from nigrostriatal D2 blockade. TD is from compensatory receptor upregulation/supersensitivity.

NMS: Life-threatening emergency. Tetrad: hyperthermia, rigidity, autonomic instability, altered consciousness. Stop antipsychotic, give dantrolene + bromocriptine, supportive ICU care.

Clozapine: Agranulocytosis (mandatory neutrophil monitoring), myocarditis, seizures, severe constipation/ileus, PE.

Functional Impairment: Cognitive impairment is the key determinant of functional outcome and represents an unmet therapeutic need (not responsive to antipsychotics). Even when positive symptoms are controlled, patients may remain disabled.

Non-adherence: Up to 52%, the major risk factor for relapse. Each relapse risks incomplete recovery and progressive decline.

Comorbid Substance Abuse: 30% abuse alcohol. Temporarily reduces isolation/anxiety but worsens psychosis, mood, non-compliance, and overall outcome.

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