Two-year trial of maintenance neuroleptic dose reduction in schizophrenic out-patients: predictors of relapse

Abstract

Low dose maintenance therapy has been proposed as a pharmacological strategy for reducing exposure to neuroleptic drugs in schizophrenia. However, reliable predictors of post-dose reduction relapse, which could guide clinicians in selecting patients suitable for this type of treatment, have not yet been determined. In this study, 41 schizophrenic out-patients were assigned, on the basis of their previously clinically determined dosages, to one of two reduced maintenance fluphenazine decanoate regimes (35 mg/4 wks. or 10 mg/4 wks.) and were assessed, subsequently, for a 2-year period. Demographic, clinical and treatment characteristics of relapsers (22 patients) and non-relapsers (18 patients) were compared using univariate and multivariate tests. Four parameters: age, course of illness, duration of illness and duration since last psychiatric hospitalization, suggested, in univariate tests, significant discrimination between relapsers and non-relapsers. Stepwise discriminant function analyses defined a highly significant function (p < .01) which included only 3 predictors of relapse. In order of importance, these predictors were: (1) a history of chronic psychosis (2) male sex, and (3) an illness of short duration. Parameters such as age, baseline rating scales scores, magnitude of dose reduction and baseline maintenance dose failed to improve the ability to discriminate between relapsers and non-relapsers. Implications of these findings for clinical practice are discussed.