During episodes of mania and depression, cognitive deficits are apparent in nearly every cognitive domain. While this cognitive disruption has been largely overlooked in the past, recent evidence indicates that cognitive deficits are also apparent during the euthymic phase and that these deficits correlate with functional outcome (reintegration to their everyday lives). To date, the underlying causes of these cognitive deficits as well as the episodes of mania and depression have yet to be elucidated.