Today, it is well-known that the ‘pure’ forms of bipolar disorder (BD), e.g. those characterized only by alternating depressive and manic episodes, are quite rare, and that BD is more often associated with other psychiatric disorders or manifestations, among which anxiety disorders/symptoms. In patients with BD, symptoms and/or dis- turbances of anxiety have a primary role for both epidemiological and clinical aspects. Particular aspects of the relationship between anxiety symptoms/disorders and BD, some of which observed by classical authors in the last century, allow for a broader reading of this link, which goes beyond the simple comorbidity: anxiety disorders are the most frequent comorbid disorders for bipolar patients; anxiety symptoms/disorders tend to persist and assume a chronic course in bipolar patients; anxiety symptoms/dis- orders are early precursors of BD in offspring of BD subjects. Evidences exist, then, suggesting that anxiety is a core component or epiphenomenon of bipolar disorders. Moreover, comorbid anxiety disorders have a significant impact on the clinical presentation and prognosis of BD. The aim of this study was to explore the correlation be- tween anxiety and BD through a critical review of the recent literature, treating both conceptual and clinical questions.
