Sleep and Depression

Depression disrupts sleep in two opposite directions — insomnia (especially early morning waking) is common, but so is hypersomnia, sleeping far more than usual and still waking unrefreshed. Either pattern can be present.

The relationship is bidirectional: insomnia is one of the strongest predictors of developing depression, and depression makes insomnia worse, so treating the sleep problem specifically — not just the mood — often improves both.

A fixed wake time is particularly important here, since oversleeping (common in depression) reduces the light exposure that helps regulate mood and further delays the body clock.

CBT-I has a strong evidence base as an add-on treatment for depression specifically, sometimes improving mood symptoms even before antidepressant treatment takes full effect. If sleep problems and low mood are both present, it's worth raising both with a doctor rather than treating them as unrelated.