Tardive Dyskinesia — MRCPsych Paper B MCQ

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EasySchizophrenia & PsychosisTardive DyskinesiaMRCPsych Paper B

A 60-year-old man who has taken chlorpromazine 300 mg daily for 15 years develops involuntary, repetitive movements of his tongue, lips and jaw, including lip-smacking and tongue protrusion. The movements are less apparent when he deliberately concentrates on suppressing them. Which extrapyramidal side effect is this?

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Correct answer: B — Tardive dyskinesia

This is tardive dyskinesia: repetitive, involuntary orofacial movements such as lip-smacking, chewing and tongue protrusion arising after prolonged exposure to a dopamine-receptor-blocking antipsychotic. The long duration of chlorpromazine treatment and characteristic oro-bucco-lingual movements are decisive. Akathisia causes subjective inner restlessness with pacing or an inability to remain still. Antipsychotic-induced parkinsonism produces rigidity, bradykinesia and typically a regular tremor. Acute dystonia usually occurs early in treatment or after a dose increase and causes sustained muscular contractions, such as torticollis or an oculogyric crisis. Neuroleptic malignant syndrome presents acutely with hyperthermia, severe rigidity, altered consciousness and autonomic instability.

Reference: Electronic Medicines Compendium. Chlorpromazine 100 mg Tablets: Summary of Product Characteristics, section 4.8, revised October 2024. https://www.medicines.org.uk/emc/product/3476/smpc