Sleep disturbance is recognized as an essential aspect of affective illness.

Multiple lines of evidence suggest that a change in sleep pattern may indicate an imminent mood change. In fact, the impaired sleep can be seen as a sign as well as a cause of manic episodes. Thus, sleep can be a predictor of mania or a marker of response and therapeutic target.

This retrospective study explores the role of insomnia in patients with Affective Bipolar Disorder presenting with current mania or hypomanic episode, based on ICD-10 criteria. It was randomly selected a sample of 61 adults admitted at Psychiatry Department of Hospital de São João between 2005-2007. It was assessed the presence of insomnia before and during the treatment and compared with the duration of the hospitalization, the number of attendances to the Emergency Department and hospitalizations one year after.

Given the importance of insomnia in bipolar illness, appropriate evaluation and management of sleep can be helpful in preventing relapses in this disorder. Therefore sleep improvement in mania may be clinically useful as therapeutic target.