Real-world effectiveness of mood stabilizer use in schizophrenia

Abstract

Objective: Mood stabilizers (MS) are often used as adjunctive medication in patients with schizophrenia. The aim of this study was to investigate the real-world effectiveness of MS use in persons with schizophrenia. Methods: The study cohort included all persons treated in inpatient care due to schizophrenia during 1972–2014 in Finland (N = 61,889). Drug purchase data were obtained from the national Prescription register and modeled with the PRE2DUP method. The follow-up period covered the years 1996–2017. Mood stabilizers included carbamazepine, valproic acid, lamotrigine, and lithium. The main outcome was psychosis hospitalization. We utilized within-individual design to compare the risk of outcome between time-periods of MS use and non-use within the same person. Stratified Cox regression analyses were conducted with adjusted hazard ratios (aHR) and 95% confidence intervals (CIs). Results: Mean age at cohort entry was 46.2 years (SD 16.0) and 50.3% were male. During the follow-up (maximum of 22 years, median 14.8 years, interquartile range 7.5–22.0), 28.1% (N = 17,370) of the study cohort used MS, valproic acid being the most often used one (60.4%, N = 10,483). Risk of psychosis hospitalization was lower during MS use than non-use (aHR 0.88, 95% CI 0.86–0.90). Use of lithium (0.84, 0.81–0.87), valproic acid (0.87, 0.85–0.90), and lamotrigine (0.90, 0.85–0.95) were associated with lower risk of psychosis hospitalization compared with their non-use, whereas carbamazepine use was not. Conclusions: Mood stabilizers were relatively often used as adjunctive treatments in schizophrenia and their use was associated with a 12% decreased risk of psychosis rehospitalization, a marker of relapse in schizophrenia.