Real‐world effectiveness of mood stabilizer use in schizophrenia

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.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).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.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.