Comparative effectiveness of long-acting injectable risperidone vs. long-acting injectable first-generation antipsychotics in bipolar disorder

Objective The aim of this study was to compare the treatment effectiveness between long-acting injectable risperidone and long-acting injectable first-generation antipsychotics among patients with bipolar disorder. Method We conducted a retrospective cohort study using Taiwan's National Health Insurance Research Database. Patients with bipolar disorder aged 15 years or higher, who were newly administered long-acting injectable antipsychotics between June 1, 2004 and December 31, 2011 were included. The clinical outcome indexes were hospitalization for any mood, manic/mixed, or depressive episodes. In addition, the all-cause discontinuation of long-acting injectable antipsychotic treatment was also assessed. Results A total of 3916 patients with bipolar disorder were extracted. Compared with risperidone, the use of first-generation antipsychotics was associated with a higher rate of hospitalization for any mood episode and major depressive episode. However, there was no statistically significant difference in treatment discontinuation rate between risperidone and first-generation antipsychotics. Limitations Information for the severity of mood symptoms, social support, life style, neurological and metabolic adverse effect was not available in this database. In addition, we only measured severe mood episodes with hospitalization as our outcome index. It may not be possible to generalize our findings to mild mood episodes. Conclusions Our findings suggested that patients treated with long-acting injectable risperidone might be superior to first-generation antipsychotics in the rate of psychiatric hospitalization.