L-dopa challenge and relapse in schizophrenia.

Neuroleptic administration has been shown to be superior to placebo in prolonging schizophrenic remission. However, individual patients are able to maintain long periods of remission in the absence of neuroleptic treatment, while others relapse soon after neuroleptic withdrawal. This study attempted to predict time to relapse in 28 schizophrenic patients withdrawn from neuroleptics and challenged with L-dopa for 7 days, then followed until relapse. Time to relapse correlated significantly with L-dopa-induced increase in BPRS score (p = .006). Five of six patients who responded to L-dopa relapsed within 4 weeks after L-dopa administration, while only four of 22 who did not respond relapsed in a comparable period.