Sleep and mood disorders.

Mood disorders are found in one-third to one-half of patients with chronic sleep problems. Likewise, most patients with mood disorders experience insomnia, but a minority obtain significantly increased amounts of sleep. Although mood disorders cause significant morbidity and mortality, they often go undiagnosed. Attention to sleep complaints could lead to better identification of mood disorders. Management of sleep problems in patients with mood disorders should focus on treating underlying mood disorders with attention to the nature of the sleep complaint. Patients with depression show characteristic abnormalities in sleep continuity, slow-wave sleep and REM sleep patterns. Differences in sleep patterns cannot reliably distinguish patients with depression from those with other psychiatric disorders, but sleep changes may provide a window on neurobiologieal abnormalities in depression.