Schizophrenia and psychotic disorders are a core component of general adult psychiatry in Paper B. The questions range from diagnostic classification using ICD-11 to antipsychotic selection guided by trial evidence. Clozapine is disproportionately represented in recall questions, reflecting its clinical importance and the detailed monitoring protocols associated with its use.
ICD-11 Diagnostic Criteria for Schizophrenia
ICD-11 simplified the diagnosis of schizophrenia compared to ICD-10. The core requirement is at least 1 of the following symptoms present for most of the time over a period of at least 1 month:
- Persistent delusions
- Persistent hallucinations (auditory, visual, or other modalities)
- Disorganised thinking (formal thought disorder)
- Experiences of influence, passivity, or control (delusions of control)
- Negative symptoms (blunted affect, alogia, avolition, anhedonia, asociality)
ICD-11 removed the subtypes (paranoid, hebephrenic, catatonic, undifferentiated, residual) that existed in ICD-10. The diagnosis now focuses on the symptom dimensions. This is a change that exam questions test: a candidate is asked which ICD-10 subtype is no longer recognised in ICD-11.
Schizophrenia vs autism spectrum: This is a recurring question. Features that favour schizophrenia over autism: near normal early development, mood-incongruent psychotic symptoms, later age of onset. Features that favour autism: impaired social communication from early childhood, restricted repetitive behaviours that precede psychotic symptoms.
Antipsychotic Management: First-Episode Psychosis
NICE guidance (CG178) recommends oral antipsychotic medication as first-line for first-episode psychosis. The choice should be made jointly with the patient, considering side-effect profile. First-line options include olanzapine, risperidone, aripiprazole, quetiapine, and amisulpride. Haloperidol is not recommended first-line due to higher EPS risk.
Key principles for first-episode treatment: start at low dose, titrate slowly, continue for 1-2 years after first episode before considering withdrawal. Relapse risk within 1 year of stopping medication is approximately 75% compared to 25% in those who continue maintenance treatment.
First episode psychosis + cardiac problem: Aripiprazole (lowest QTc prolongation, least metabolic impact).
Trial Evidence: CATIE and CUtLASS
The two major trials comparing antipsychotics appear regularly in Paper B.
CATIE (2005): 1,493 patients with schizophrenia, randomised to olanzapine, risperidone, quetiapine, ziprasidone, or perphenazine. Olanzapine had the lowest discontinuation rate but the greatest weight gain and metabolic effects. Perphenazine was comparable to atypicals for efficacy. No significant difference in cognitive improvement between the drugs.
CUtLASS (2006): 227 patients with schizophrenia, randomised to FGAs (sulpiride, haloperidol, trifluoperazine) or SGAs. No significant advantage for SGAs over FGAs in quality of life, symptoms, or cost. First-generation antipsychotics are not inferior for efficacy.
Exam takeaway: Antipsychotic choice should be guided by individual patient factors and side-effect profiles, not by assuming atypical = more effective.
Clozapine: Detailed Knowledge Required
Clozapine is the most heavily tested single drug in Paper B. Indications: treatment-resistant schizophrenia (failure of at least 2 antipsychotics at adequate dose for 6-8 weeks, at least one atypical). Monitoring: FBC weekly for 18 weeks, fortnightly to 52 weeks, then monthly. WCC <3.0 or neutrophils <1.5 = stop immediately, daily FBC until recovery. Rechallenge not recommended after neutropenia.
Side effects tested in recalls:
- Myocarditis: First 2 months. Tachycardia, chest pain, fever, elevated troponin. Saddle-type ST elevations on ECG. Stop clozapine, cardiology review. Do NOT rechallenge.
- Cardiomyopathy: Late complication (>6 months). Reduced ejection fraction on echocardiogram.
- Constipation: Up to 60%. Can be fatal (bowel obstruction/perforation). Aggressive laxatives.
- Sialorrhoea: Worse at night. Hyoscine or amitriptyline.
- Tachycardia: 20-30 bpm above baseline. Beta-blocker after excluding myocarditis.
- Seizures: Dose-dependent, risk rises above 600mg/day. Dose reduction or valproate augmentation.
- Weight gain and metabolic syndrome: Most significant metabolic side-effect profile of any antipsychotic.
Clozapine + persistent symptoms at 3 months: Check compliance FIRST. Clozapine takes longer to reach full effect and non-adherence is common. If compliance confirmed and therapeutic levels achieved, augment with aripiprazole or amisulpride.
Clozapine + ECT: Clozapine lowers seizure threshold, which can be useful in TRS where ECT is being considered.
High-Yield Recall Patterns for Psychosis
- First-episode psychosis + cardiac problem: Aripiprazole
- Clozapine + tachycardia + high troponin: Myocarditis. Stop clozapine.
- Clozapine + persistent hallucinations at 3 months: Check compliance first.
- Tardive dyskinesia on flupentixol depot for 20 years: Lower the depot dose first.
- Which favours schizophrenia over autism: Near normal early development, mood-incongruent symptoms, catatonia.
- Amisulpride low vs high dose: Below 400mg presynaptic (negative symptom benefit), above 400mg postsynaptic (antipsychotic effect).
- CATIE key finding: Olanzapine lowest discontinuation, worst metabolic.
- CUtLASS key finding: No superiority of atypicals over typicals for quality of life.
PsychStar’s Paper B question bank covers schizophrenia and psychosis with questions calibrated to real exam style. Try 5 free questions at psychstar.io/try.