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Antipsychotic Response Timeline — MRCPsych Paper B MCQ

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ModerateSchizophrenia & PsychosisAntipsychotic Response TimelineMRCPsych Paper B

A 29-year-old man with first-episode non-affective psychosis starts oral olanzapine 10 mg daily, with planned titration according to response and tolerability. Adherence is confirmed and he has no intolerable adverse effects. He asks when improvement should be expected and when efficacy can fairly be judged. Which statement is most accurate?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Improvement may begin within 1–2 weeks; assess an adequate trial after 4–6 weeks at optimum dosage.

Explanation lettering: D = shown as A · A = shown as B · B = shown as C · E = shown as D · C = shown as E

B is correct. Antipsychotic action is not necessarily delayed for several weeks: measurable improvement in psychotic symptoms may begin during the first 1–2 weeks and then accumulate. However, early change is not equivalent to completion of an adequate therapeutic trial. NICE recommends an antipsychotic trial at the optimum dosage for 4–6 weeks, while monitoring adherence, symptoms, behaviour and adverse effects. Sedation within 24 hours is not evidence of a complete antipsychotic response, so A is incorrect. Absence of improvement at an early assessment may predict a poorer eventual response but does not prove treatment failure. Waiting 3 months, 6–12 months or until after 8 weeks before assessing efficacy is inconsistent with the standard NICE trial period.

Reference: National Institute for Health and Care Excellence. Psychosis and schizophrenia in adults: prevention and management (CG178), recommendation 1.3.6.3. 2014. https://www.nice.org.uk/guidance/cg178/chapter/recommendations