Prevalence and impact of comorbid anxiety and bipolar disorder.

Comorbid conditions pose a serious risk to patients with bipolar disorder, but anxiety comorbidity poses a specific hazard due to the increased negative impact of anxiety on illness course and treatment. Anxiety comorbidity appears to be highly prevalent and is associated with intensified symptoms of bipolar disorder and additional comorbid disorders, resulting in a negative impact on the patient and on the course of the illness. The presence of anxiety in bipolar patients is also associated with a lowered age at onset, hampered patient response to treatment such as lithium, increased rates of suicide and substance abuse, and decreased quality of life. Patients can experience work, family, and social impairment and be made to contend with increased health care costs and strains on family support. Studies are few and have a limited scope, and many have failed to consider the clinical significance of comorbid anxiety and bipolar disorder. Because the degree to which anxiety impacts patients with bipolar disorder is not fully known, more information is needed about the relationship between bipolar disorder and anxiety.