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February 1971

Motor Disorders Induced by NeurolepticsA Proposed New Classification

Author Affiliations

From the Psychopharmacology Research Branch (Dr. Crane) and the Computer Systems Branch (Mrs. Naranjo), the National Institutes of Mental Health, Chevy Chase, Md. Dr. Crane is now at the Spring Grove State Hospital, Catonsville, Md.

Arch Gen Psychiatry. 1971;24(2):179-184. doi:10.1001/archpsyc.1971.01750080083014

A comprehensive classification of motor disorders attributed to neuroleptic drugs is proposed. Some manifestations resemble those occurring in known diseases of the central nervous system; other abnormalities are typical effects of drugs with neuroleptic action. A factor analysis on the most frequently occurring motor disorders generated the following symptom clusters: (1) tremor, bradykinesia, rigidity, and attendant symptoms; (2) buccolingual-masticatory dyskinesia, astasia, dyskinesia of the lower extremities and posture in extension; and (3) dyskinesia of the upper extremities and postural disorder. The classification and the factors were used to study the effects of drug withdrawal on a sample of patients over a sixmonth period. Symptoms of cluster 1 decreased while those of cluster 2 increased in severity. In a control group receiving standard drugs during a comparable period, no significant changes were noted.