Clozapine withdrawal catatonia associated with cholinergic and serotonergic rebound hyperactivity: a case report.

Catatonia as a clozapine withdrawal syndrome has not been well documented. There is only 1 case of excited catatonia described with the diagnosis made according to strict criteria. The authors report a patient who developed a catatonic stuporous state following abrupt discontinuation of clozapine, associated with features of cholinergic and serotonergic hyperactivity. The catatonic state resolved within 1 week with reinstatement of clozapine. It is suggested that serotonergic hyperactivity was involved, contributed by cholinergic rebound, in the pathogenesis of this patient's clozapine withdrawal catatonic syndrome.