Prospective 12-month course of bipolar disorder in out-patients with and without comorbid anxiety disorders.

BACKGROUND The impact of anxiety disorders has not been well delineated in prospective studies of bipolar disorder. AIMS To examine the association between anxiety and course of bipolar disorder, as defined by mood episodes, quality of life and role functioning. METHOD A thousand thousand out-patients with bipolar disorder were followed prospectively for 1 year. RESULTS A current comorbid anxiety disorder (present in 31.9% of participants) was associated with fewer days well, a lower likelihood of timely recovery from depression, risk of earlier relapse, lower quality of life and diminished role function over I year of prospective study. The negative impact was greater with multiple anxiety disorders. CONCLUSIONS Anxiety disorders, including those present during relative euthymia, predicted a poorer bipolar course. The detrimental effects of anxiety were not simply a feature of mood state. Treatment studies targeting anxiety disorders will help to clarify the nature of the impact of anxiety on bipolar course.