Objectives: Prior research suggests possible gender differences in the longitudinal course of bipolar disorder. This study prospectively examined gender differences in mood outcomes and tested the effects of sexual/physical abuse and posttraumatic stress disorder (PTSD).
Methods: Participants (49 men, 41 women) with co-occurring bipolar I and substance use disorders (92% alcohol, 42% drug) were enrolled in a group treatment trial. They were followed for eight months, with monthly assessments, yielding 32 weeks of data. Primary outcome measures were number of weeks in each mood state, recurrences of depression or mania, and polarity shifts from depression to mania or vice versa. Negative binomial regression was used to examine the effects of gender, lifetime abuse, and PTSD on these outcomes.
Results: Participants met syndromal criteria for a mood episode on a mean of 27% of 32 weeks, with depression occurring most frequently. Compared to men, women reported significantly more weeks of mixed mania [relative rate (RR) = 8.53], fewer weeks of euthymia (RR = 0.58), more recurrences of mania (RR = 1.96), and more direct polarity shifts (RR = 1.49) (all p < 0.05). Women also reported significantly higher rates of lifetime sexual or physical abuse (68% versus 33%), which partially explained the relationships between gender and mixed mania and direct polarity shifts.
Conclusions: Participants experienced persistent mood symptoms over time. Women consistently reported poorer mood outcomes, and lifetime abuse may help explain observed gender differences in mood outcomes. Further research is necessary to better understand the treatment implications of these findings.