Impact of comorbid anxiety disorders and obsessive-compulsive disorder on 24-month clinical outcomes of bipolar I disorder.

BACKGROUND This study investigated the impact of comorbid obsessive-compulsive disorder (OCD) and four anxiety disorders [panic disorder (PD), agoraphobia, social anxiety disorder (SAD), and generalized anxiety disorder (GAD)] on the clinical outcomes of bipolar disorder. METHODS This study analysed data of 174 patients with bipolar I disorder who participated in the prospective observational study. Participants were assessed every 3 months for 24 months. The primary outcome measure was the achievement of symptomatic remission, defined by a total score on the Young Mania Rating Scale (YMRS) of ≤12 and a total score on the 21-item Hamilton Depression Rating Scale (HAMD-21) of ≤8. RESULTS Comorbidity was associated with decreased likelihood of remission. However, the impact of individual disorders on outcome differed according to clinical and treatment situations. Most comorbid anxiety disorders and OCD had a negative effect on remission during the first year of evaluation, as measured by the HAMD-21, and in patients taking a conventional mood stabilizer alone. However, the association with poorer outcome was observed only for a few specific comorbid disorders in the second year (GAD and OCD), as measured by YMRS-defined remission (OCD), and in patients with olanzapine therapy (GAD and OCD). LIMITATIONS Follow-up evaluation of comorbid disorders was lacking. CONCLUSIONS Comorbid anxiety disorders and OCD negatively influenced the clinical course of bipolar disorder. Specifically, OCD had a consistently negative impact on the outcome of bipolar I disorder regardless of clinical situation. Effective strategies for the control of these comorbidities are required to achieve better treatment outcomes.