Prediction of early relapse after pimozide discontinuation by response to d-amphetamine during pimozide treatment
Van Kammen, D.P.; Docherty, J.P.; Bunney, W.E.
Biological Psychiatry 17(2): 233-242
1982
ISSN/ISBN: 0006-3223 PMID: 7074181 Document Number: 187062
Thirteen schizophrenic patients underwent a d-amphetamine infusion while being treated with pimozide, an antipsychotic agent and a relatively specific dopamine (DA) blocker. Six patients who showed an acute increase in psychosis with d-amphetamine relapsed within 3 months after pimozide withdrawal. Of the seven patients who did not change in psychosis with d-amphetamine, six did not relapse after pimozide discontinuation (Fisher's exact test, p less than 0.005). Retrospectively, the psychosis-inducing effects of d-amphetamine were found to be predictive of psychotic exacerbation following subsequent pimozide withdrawal. Pimozide failed to block the psychotogenic effects of d-amphetamine in six patients indicating that other mechanisms besides DA may play a role in psychotic decompensation. The d-amphetamine infusion paradigm should be studied further to determine its clinical value for identifying which schizophrenic patients are at risk for relapse after discontinuation of neuroleptic treatment.