Sleep disturbance is one of the most common problems facing older adults with nearly 60% of them reporting sleep problems at least a few nights a week. Unfortunately sleep problems are often considered to be a normal part of ageing despite the fact that sleep disturbance is linked to declines in health, increases in mortality and depression. People who have had depression before tend to be more at risk of having it in the future but little research has been done into whether lack of sleep contributes to a recurrence of depression. A U.S. study of 351 older adults compared 145 people with a history of depression to 206 people who had never had any mental illness. 16.9% of the people who had previously had depression developed it again over the course of the 2-year study compared to only one person in the group who had never had mental illness. Within the group who had previously had depression recurrence was predicted by sleep disturbance; a link that was independent of other depressive symptoms, chronic medical disease and antidepressant medication use.
Cho, Hyong Jin ... [et al] - Sleep disturbance and depression recurrence in community-dwelling older adults: a prospective study American Journal of Psychiatry December 2008, 165(12), 1543-1550