Mixed Bipolar patients are those who have co-existing depressive symptoms during mania. These patients are supposed to have a worse evolution.

The objective of this study was to compare the long-term outcomes of patients who had at least one mixed episode with those who experienced only pure manic episodes.

169 outpatients diagnosed of Bipolar I disorder and treated at least during two years were included. 120 patients (71%) complited the follow-up over 10 years. Baseline demographic and clinical variables were included.

The patients with mixed episodes (37%) had a significantly younger mean age at onset comparing with those with manic episodes (25.3 years vs. 30.8 years; p=0.025) they also had more previous mood- incongruent psychotic symptoms χ2= 6.77, p=0.034), more number of hospitalizations (OR= 1.36, 95% CI = 1.14; -1.63; p< 0.001), and more number of episodes (OR= 1.21, 95% CI = 1.10-1.31; p< 0.001). There were no significant differences relating to depressive episodes, alcohol use, drug abuse, suicidal behaviour and suicide attempts.

Age at onset differed significantly between the mixed episode and pure mania groups, with mixed episode patients having a younger age of onset. This is interesting as one of the major results of the study we have found that age at onset mediates some of the factors classically related to outcome in mixed episodes like alcohol abuse and suicide attempts. However, independently of age at onset, these patients represent a especially severe type of bipolar disorder.