Longitudinal analysis of abnormal involuntary movements in long-term clozapine-treated patients

As part of a prospective efficacy and safety monitoring system, patients receiving clozapine are assessed monthly for dyskinetic events (DE), using the Abnormal Involuntary Movement Scale (AIMS). Longitudinal analysis of 45 patients revealed 20 with baseline DE, 7 who developed emergent DE after a negative baseline assessment, and 18 patients with no DE symptoms throughout treatment with clozapine. Eight of the 20 patients with baseline DE were assessed to resolution of symptoms, with an average time of 261+/-188 days; 5 were evaluated until complete resolution of symptoms (AIMS=0), with an average time of 691+/-462 days. The average time to onset of DE in emergent DE patients was 238+/-179 days, and the average time to resolution was 347+/-179 days after diagnosis. Four patients attained complete resolution with an average time of 629+/-293 days after diagnosis. It appears this emergent type of dyskinesia is different from other currently described dyskinesias. Overall, of the 27 patients having DE at any point in treatment, 15 of 27 (56%) had resolution of symptoms and 10 of 27 (37%) had complete resolution of DE. Clinicians should be aware of the utility of clozapine in dyskinesia and the extended time frame of response.