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

Background: There 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.

Methods: Institutionalized 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.

Results: A 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).

Conclusion: Switching from a combination of FGA and SGA to monotherapy in long-term inpatients does not increase the relapse rate and may even reduce it.

Keywords: Antipsychotics; Polypharmacy; Relapse; Schizophrenia; Switching.