Reward sensitivity and the course of bipolar disorder: A survival analysis in a treatment seeking sample

Objectives: Reward sensitivity is suggested to be an influence on the onset and reoccurrence of bipolar disorder (BD) in observational longitudinal studies. The current study examined whether reward sensitivity predicted the recurrence of mood episodes in a treatment seeking sample. We also explored if reward sensitivity moderated treatment outcomes of psychosocial treatment. Methods: Seventy-six euthymic adult patients with BD were randomly assigned to either Cognitive Behavioral Therapy (CBT) or Supportive Therapy (ST) and followed up for 2 years after completing therapy (Meyer and Hautzinger, 2012). The primary outcome measure was recurrence of mood episodes. The final multivariate Cox regression models included potential covariates, therapy conditions, BAS reward sensitivity, and the interaction between BAS and therapy conditions. Results: BAS emerged as the only significant predictor of time till recurrence of mania, but not depression, but the overall model did not reach significance. There was no interaction between treatment and BAS reward sensitivity. Interestingly, a diagnosis of BD II predicted time till recurrence of depression. Conclusion: The main result regarding BAS partially confirms prior studies linking BAS and mania, but power and the specific sample seeking psychosocial treatment might have reduced the effect.