Some individuals with bipolar disorder transition directly from major depressive episodes to manic, hypomanic, or mixed states during treatment, even in the absence of antidepressant treatment. Prevalence and risk factors associated with such transitions in clinical populations are not well established, and were examined in the Systematic Treatment Enhancement Program for Bipolar Disorder study, a longitudinal cohort study. Survival analysis was used to examine time to transition to mania, hypomania, or mixed state among 2166 bipolar I and II individuals in a major depressive episode. Cox regression was used to examine baseline clinical and sociodemographic features associated with hazard for such a direct transition. These features were also examined for interactive effects with antidepressant treatment. In total, 461/2166 subjects in a major depressive episode (21.3%) transitioned to a manic/hypomanic or mixed state before remission, including 289/1475 (19.6%) of those treated with antidepressants during the episode. Among the clinical features associated with greatest transition hazard were greater number of past depressive episodes, recent or lifetime rapid cycling, alcohol use disorder, previous suicide attempt, and history of switch while treated with antidepressants. Greater manic symptom severity was also associated with risk for manic transition among both antidepressant-treated and antidepressant-untreated individuals. Three features, history of suicide attempt, younger onset age, and bipolar subtype, exhibited differential effects between individuals treated with antidepressants and those who were not. These results indicate that certain clinical features may be associated with greater risk of transition from depression to manic or mixed states, but the majority of them are not specific to antidepressant-treated patients.
Keywords: bipolar disorder, mania, switch, antidepressant, adverse effect