Sleep disturbance and cognitive deficits in bipolar disorder: toward an integrated examination of disorder maintenance and functional impairment.

Bipolar disorder is frequently associated with a number of poor outcomes including, but not limited to, a significant impairment in the ability to return to premorbid levels of occupational and psychosocial functioning, often despite the remission of mood symptoms. Sleep disturbance is an oft-reported residual symptom of manic and depressive episodes that has likewise been associated with the onset of manic episodes. Also present during affective episodes as well as the inter-episode periods are reports of deficits in cognitive functioning, which many reports have shown to play an important role in this persistent disability. Despite the presence of deficits in these two domains of functioning during affective episodes as well as the inter-episode phase, there has been no evaluation of the degree to which these systems may interact to maintain such high rates of functional disability. The aim of this review is to examine evidence for the study of the relationship between sleep disturbance and cognitive impairments in bipolar disorder as well as the ways in which deficits in these domains may work together to maintain functional impairment.