Risk of treatment discontinuation and psychiatric hospitalization associated with early dose reduction of antipsychotic treatment in first‐episode schizophrenia: A nationwide, health insurance data–based study

Abstract

Aim We investigated the impact of early dose reduction of antipsychotic treatment on the risk of treatment discontinuation and psychiatric hospitalization in patients with first‐episode schizophrenia (FES). Methods The Health Insurance Review Agency database in South Korea was used to include 16 153 patients with FES. At 6 months from their diagnosis, the patients were categorized by the magnitude of dose reduction (no reduction, 0%–50%, and >50%). With a reference of no reduction, the risk of treatment discontinuation and psychiatric hospitalization associated with dose reduction in the 1‐year follow‐up period after the first 6 months was examined with a Cox proportional hazard ratio model stratified by the mean daily olanzapine‐equivalent dose in the first 3 months (<10, 10 to 20, >20 mg/day). Results A >50% dose reduction was associated with an increased risk of treatment discontinuation in all subgroups (<10 mg/day: hazard ratio [HR] =1.44, 95% confidence interval [CI] =1.24–1.67 [P <0.01]; 10–20 mg/day: HR =1.60, 95% CI =1.37–1.86 [P <0.01]; and >20 mg/day: HR =1.62, 95% CI =1.37–1.91 [P <0.01]). In the subgroup taking <10 mg/day, an association of 0%–50% dose reduction with an increased risk of treatment discontinuation was observed (HR =1.20, 95% CI =1.09–1.31; P <0.01). A > 50% dose reduction was associated with increased risk of psychiatric hospitalization only in the subgroup taking <10 mg/day (HR =1.48, 95% CI =1.21–1.80; P <0.01). Conclusions Our results suggest that an above certain dose of antipsychotic drugs is required to prevent psychiatric hospitalization, and extensive dose reduction of antipsychotic drugs could result in a higher risk of treatment discontinuation.