Sleep and Depression

Numerous studies provide findings indicating the remarkable relationship between sleep alterations and depression. Although the existing hypotheses are not likely to explain all aspects of the sleep alterations in depression, each may be worth being maintained for refinements of pathophysiologic models of depression as new data accumulate. Further research taking into account the heterogeneity of depressive disorder and linking the different areas of research is needed to develop more comprehensive theoretical models and new therapies for depression.