Objective: To assess the relative contribution of different drugs of abuse to extrapyramidal side effects (EPS) of antipsychotic drugs.
Method: 106 consecutively contacted or admitted male patients in the Psychiatric Center of Surinam (PCS) with schizophrenia or a related disorder were included. Prevalence and severity of EPS were measured with the Unified Parkinson's Disease Rating Scale (UPDRS), the Abnormal Involuntary Movement rating Scale (AIMS), the Barnes Akathisia Rating Scale (BARS) and the Dystonia rating scale. Recent use of cigarettes, cannabis, alcohol, and cocaine were assessed. Standard multiple regression analyses were used to evaluate the relative contribution of above-mentioned drugs of abuse controlled for milligrams haloperidol equivalent a day and use of anticholinergic medication.
Results: Recent cocaine use was significantly associated with severity of dyskinesia (p = 0.001), parkinsonism (p = 0.007), and akathisia (p < 0.001) (n = 106).
Conclusions: Recent cocaine use is a major risk factor for antipsychotic induced EPS.