Catatonic reactions to high-potency neuroleptic drugs.

Eight patients developed a syndrome marked by features of catatonia (including posturing, waxy flexibility, withdrawal and regression) and parkinsonism (including bradykinesia and rigidity) while receiving high-potency neuroleptic drugs. The syndrome had a gradual onset, responded slowly to withdrawal of the neuroleptic or use of an anticholinergic agent, but seemed to respond more rapidly to amantadine. The syndrome may easily be confused with a worsening of schizophrenic symptoms.