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Parkinson's Psychosis — MRCPsych Paper B MCQ

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ModerateOld Age PsychiatryParkinson's PsychosisMRCPsych Paper B

A 68-year-old man with Parkinson's disease develops recurrent visual hallucinations of small animals, which he finds distressing. General medical evaluation identifies no delirium or other physical trigger, and he has no cognitive impairment. Specialist-led reduction of recently increased antiparkinsonian medication has not resolved the hallucinations, so antipsychotic treatment is being considered. Which antipsychotic is most appropriate because it has the least risk of worsening his parkinsonism?

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Correct answer: E — Quetiapine

The correct answer is E, quetiapine. NICE recommends considering quetiapine for hallucinations or delusions in Parkinson's disease when there is no cognitive impairment, using lower doses than for other indications. The stem establishes that the hallucinations are distressing, physical triggers have been excluded and adjustment of antiparkinsonian medication has been insufficient. Clozapine, although not listed, is offered if standard treatment is ineffective and requires blood monitoring. Haloperidol is contraindicated in Parkinson's disease. Risperidone and amisulpride may worsen parkinsonism through dopamine blockade and commonly cause extrapyramidal effects. NICE specifically advises against olanzapine because it can worsen motor symptoms and has not shown benefit for Parkinson's psychosis.

Reference: National Institute for Health and Care Excellence. Parkinson's disease in adults (NG71), section 1.5: Psychotic symptoms, recommendations 1.5.12–1.5.20. 2017; last reviewed 2024. https://www.nice.org.uk/guidance/ng71/chapter/Recommendations