Amphetamine response and relapse risk after depot neuroleptic discontinuation.

Twenty-five schizophrenic outpatient subjects in a depot neuroleptic discontinuation study received an amphetamine challenge approximately 6 weeks after their last dose. Only five of these showed greater than three-point increases in positive symptoms on the BPRS, and all five relapsed within 30 days of the challenge. The 20 with less than three-point increases in positive symptoms showed extremely variable stability, relapsing from 20- greater than 600 days after the challenge. Thus, increase in positive symptoms after amphetamine may identify a group at risk for rapid relapse after neuroleptic discontinuation, but lack of such a response gives little prognostic information.