The effect on relapse rate and psychiatric symptomatology: Switching a combination of first- and second-generation antipsychotic polypharmacy to antipsychotic monotherapy in long-term inpatients with schizophrenia and related disorders. A pragmatic randomized open-label trial (SwAP trial)

Abstract

BackgroundThere is little evidence to support the use of antipsychotic polypharmacy, and there are concerns about safety and side effects. Nonetheless, it is commonly used in the treatment of long-term inpatients with schizophrenia. This study investigated the effects of switching from a combination of first- and second-generation antipsychotics (FGA and SGA) to monotherapy (FGA or SGA) on relapse rates and psychiatric symptomatology. MethodsInstitutionalized patients with chronic psychotic disorders using a combination of SGA and FGA (n = 136) participated in a randomized open-label trial. The SWITCH group discontinued either FGA or SGA, the STAY group continued combination treatment. Relapse and psychotic symptoms were measured at baseline and during follow-up at 3, 6, and 9 months. Psychiatric symptomatology was measured using the Brief Psychiatric Rating Scale (BPRS). Relapse was defined as (i) an increase in BPRS score of at least 2 points on any item, or (ii) an increase of at least 4 points in total BPRS score and an adjustment of antipsychotics. ResultsA logistic regression model, corrected for sex, showed that the probability of relapse was significantly lower in the SWITCH group: 0.29 (95% CI 0.13–0.62). The protective effect of switching to monotherapy was attributable to patients continuing clozapine as monotherapy. For patients who did not experience a relapse nor dropped out, BPRS total scores decreased significantly more in the SWITCH group (p = 0.0001). ConclusionSwitching from a combination of FGA and SGA to monotherapy in long-term inpatients does not increase the relapse rate and may even reduce it.