Chronobiological aspects of bipolar disorder

Background Numerous symptoms of bipolar disorder are regulated by the circadian rhythm. Because of this association it is assumed that disruption of the circadian rhythm may be part of the pathomechanism of bipolar disorder. Objectives A comparison and subsequent critical discussion of the current data situation on chronobiological aspects of bipolar disorder are presented. Methods A narrative literature search was carried out and the main findings are presented in a summarized form. Results There are a large number of animal and human studies investigating the connection between disorders of the circadian rhythm and bipolar disorder. Especially chronotype, the environmental factor light and sleep disorders seem to be associated with the development of bipolar disorder. Conclusions The neurobiology of bipolar disorder shows numerous chronobiological aspects. There is evidence for a direct connection of disruption of the circadian rhythm and development and progression of bipolar disorder; however, at present there is no proof for the specificity of these findings for bipolar disorder. Future studies should consolidate the evidence on the impact of disorders of the circadian rhythm on the pathomechanism of bipolar disorder.