Antipsychotic Selection — MRCPsych Paper B MCQ

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ModerateSchizophrenia & PsychosisAntipsychotic SelectionMRCPsych Paper B

A 25-year-old man experiencing a first episode of psychosis agrees to start oral antipsychotic treatment. His BMI is 31 kg/m², and his father has type 2 diabetes. Following discussion of the differing adverse-effect profiles, minimising weight gain and glucose dysregulation is his main priority. Which antipsychotic has the lowest metabolic liability among the options listed?

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Correct answer: B — Aripiprazole

Aripiprazole has the lowest metabolic liability among the listed drugs and is therefore the best choice when minimising weight gain and glucose dysregulation is the stated priority. This is particularly relevant because obesity and a first-degree family history of type 2 diabetes increase this patient's baseline metabolic risk. Olanzapine and clozapine have particularly adverse weight, lipid and glycaemic profiles; clozapine is also normally reserved for schizophrenia that has not responded to two adequate antipsychotic trials. Quetiapine and chlorpromazine also have greater weight-gain and metabolic liability than aripiprazole. Aripiprazole is not metabolically risk-free, so NICE baseline and follow-up physical-health monitoring remains necessary. Its other adverse effects, particularly akathisia and impulse-control disorders, should also be discussed during shared decision-making.

Reference: Pillinger T et al. Comparative effects of 18 antipsychotics on metabolic function in patients with schizophrenia: a systematic review and network meta-analysis. Lancet Psychiatry. 2020;7:64–77. https://pubmed.ncbi.nlm.nih.gov/31860457/