Unipolar mania over the course of a 15-year follow-up study.

Objective: A proportion of patients with bipolar disorder (BD) manifests with only Unipolar mania (UM). We conducted a follow-up study of patients diagnosed with Unipolar mania and compared them as a group if they had a mild depressive episode with those who did not.

Method: 248 subjects were prospectively followed-up to 15 years. During the 15-year follow-up study, Pure mania was defined as patients who did not experience mild depressive episodes(203) and Mania with mild depression was defined as patients who did experience mild depressive episodes(45). Then, we compare characterization of clinical features between Pure mania (PM) and Mania with mild depression (MMD).

Results: Compared with the Mania with mild depression group, the Pure mania group had more psychotic symptoms, fewer suicidal behaviors, a higher proportion of morningness chronotype, better sleep quality, higher extraversion, lower neuroticism, and less harm avoidance personality traits. Substantially different lifetime comorbidity patterns were observed between the two groups.

Conclusion: Patients with Pure mania exhibited distinct clinical and psychosocial features compared with patients with the Mania with mild depression. Further studies are warranted to investigate the underlying mechanisms for diverse presentations in subgroups of BDs.

Limitations: These results apply to a relatively short outcome period, and the sample size is relatively small.