Early dyskinesia--vulnerability.

Relative vulnerability to dyskinesia in terms of exposure to antipsychotic drugs prior to onset of dyskinesia was studied in a sample of 100 psychiatric patients with dyskinesia onset generally within a year or less of the point of study entry. Unipolar and bipolar patients were more vulnerable to dyskinesia than other diagnostic groups. In the total sample, lithium exposure did not appear to delay development of dyskinesia. Longer exposure to antiparkinson drugs was associated with delayed onset of dyskinesia. Past exposure to electroconvulsive therapy was related to decreased vulnerability to dyskinesia.