Epidemiological and clinical studies have reported a high prevalence of anxiety symptoms in
bipolar disorder, either in manic or depressive episodes, although these symptoms do not always meet criteria for a specific
anxiety disorder. In addition to anxiety symptoms,
bipolar disorder frequently presents with co-morbid axis I conditions, with
anxiety disorders being the most common co-morbidity. Therefore, the objective of this article is to review clinical and epidemiological studies that have investigated the association between
bipolar disorder and anxiety. Available data on the efficacy of treatments for
bipolar disorder and co-morbid
anxiety disorders are also reviewed. Existing guidelines do recognize that co-morbid anxiety has a negative impact on the course and outcome of
bipolar disorder; however, there have been very few double-blind, controlled trials examining the treatment response of patients with
bipolar disorder and co-occurring
anxiety disorders. There is some positive evidence for
quetiapine,
olanzapine in combination with
fluoxetine or
lithium, and
lamotrigine with
lithium, and negative evidence for
risperidone. Other
therapies used for
bipolar disorder, including several mood stabilizers,
antidepressants, atypical antipsychotics and
benzodiazepines, have been shown to reduce anxiety symptoms, but specific data for their effects in patients with anxiety symptoms co-morbid with
bipolar disorder are not available. The co-occurrence of anxiety and
bipolar disorder has implications for diagnosis, clinical outcome, treatment and prognosis. Careful screening for co-morbid anxiety symptoms and disorders is warranted when diagnosing and treating patients with
bipolar disorder.