Objectives: To ascertain the clinical implications of psychiatric comorbidity in the course and outcome of bipolar I patients.
Methods: One hundred and twenty-nine bipolar I outpatients in remission [Young Mania Rating Scale (Y-MRS) < 7, Hamilton Depression Rating Scale (HDRS) < 9] were assessed by means of the Structured Clinical Interview for DSM-III-R axis I and axis II (SCID-I and SCID-II) in order to detect all possible psychiatric comorbid diagnoses. The sample was split according to the presence of psychiatric comorbidity and the groups were compared.
Results: Psychiatric comorbidity was detected in 31% of the sample. A higher number of mixed features, depressive episodes and suicide attempts and a predominance of depressive onset amongst comorbid bipolar patients were the most relevant differences between the two groups.
Conclusions: There is an association between depression, suicidality and comorbidity in bipolar I disorder. As comorbidity had a clear relevance in the course and outcome of bipolar illness, this issue should be specifically assessed in clinical practice.