Insomnia, depression and aging. Assessing sleep and mood interactions in older adults.

Insomnia and depression are related to each other on the level of epidemiology, clinical presentation, neurobiology, and treatment implications. The changes in sleep seen in older adults make these relationships particularly strong. Epidemiological studies show that depression is one of the strongest risk factors for current insomnia, but recent evidence indicates that this relationship is bi-directional: current insomnia is a risk factor for future depression. Changes in objective measures of sleep in depression mirror the changes seen in the aging process. Treating sleep disturbances may improve outcomes in patients with depression. Physicians should routinely question their older patients about sleep problems and depression.