Letting go of the bad: deficit in maintaining negative, but not positive, emotion in bipolar disorder.

Bipolar disorder is a disorder of emotion regulation. Less is known, however, about the specific processes that foster the maintenance of such prolonged and intense emotions-particularly positive-over time in this disorder. We investigated group-related differences in the ability to maintain positive and negative emotion representations over time using a previously validated emotion working memory task (Mikels et al., 2005, 2008) among individuals with bipolar I disorder (BD; n = 29) compared with both major depressive disorder (MDD; n = 29) and healthy control (n = 30) groups. Results revealed that the BD group exhibited a selective deficit in maintaining negative-but not positive-emotions compared to both the MDD and the control groups. The MDD and control groups did not differ significantly. These findings suggest that the heightened magnitude and duration of positive emotion observed in BD may, in part, be accounted for by difficulties maintaining negative emotions.