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.