Use or abuse of antiparkinsonian drugs by psychiatric patients.

The abuse of antiparkinsonian drugs was investigated in 108 aftercare patients receiving both neuroleptics and antiparkinsonian drugs. Seventy-six patients who did not show clinical extrapyramidal symptoms (EPS) were asked to reduce the dose by half or to discontinue their antiparkinsonian drug. Of these, 27 were experiencing mild EPS (subclinical) at baseline and showed reluctance or refused to reduce or discontinue their antiparkinsonian drug. Of the remaining 49 patients, 24 agreed to reduce the dose by half, and 25 agreed to discontinue their antiparkinsonian drug. During 12 weeks of follow-up, 75% of the reduced dosage group and 62.5% of the discontinued group developed clinical EPS. Nine patients (18.3%) dropped out of treatment. These results suggest that patients without clinical EPS may still experience uncomfortable symptoms (subclinical EPS), and that this is related to their desire to continue taking antiparkinsonian drugs. Antiparkinsonian drug abuse was not seen in this patient population. It is suggested that discontinuation of antiparkinsonian drugs may lead to premature termination of treatment.