Nigrostriatal EPS — MRCPsych Paper B MCQ
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Correct answer: C — Nigrostriatal
The correct answer is C, the nigrostriatal pathway. Dopaminergic projections from the substantia nigra to the striatum contribute to the regulation of movement. Antipsychotic D2 receptor blockade in this system disrupts striatal motor control and can cause extrapyramidal effects, including parkinsonism, acute dystonia and akathisia. Mesolimbic D2 blockade is principally associated with improvement in positive psychotic symptoms. Mesocortical dopamine dysfunction is linked with negative and cognitive symptoms, while tuberoinfundibular D2 blockade removes dopamine-mediated inhibition of prolactin release and may cause hyperprolactinaemia. The diencephalospinal pathway is not the principal site responsible for antipsychotic-induced parkinsonism.
Reference: PubMed, Antipsychotic Treatment of Behavioral and Psychological Symptoms of Dementia (BPSD): Management of Extrapyramidal Side Effects, pathophysiological mechanism of antipsychotic-induced EPS, 2019. https://pubmed.ncbi.nlm.nih.gov/31607910/