Delirium secondary to anticholinergics.

We present a case of a young man who developed sudden deterioration in his physical and mental state whilst being treated as an inpatient for substance-induced psychosis. This deterioration was manifested by sudden disorientation, change in behaviour and visual hallucinations. It was only after excluding other potential causes that this presentation was attributed to the regular administration of procyclidine that was being used to counteract the extrapyramidal side effects from antipsychotics. The patient showed a dramatic improvement on stopping procyclidine. This case highlights the importance of awareness of rare adverse drug reactions and the resultant distressing effect for the patient himself.