For a small percentage of depressed patients, missing a night's sleep induces a temporary sense of euphoria.

Keeping depressed patients awake is more difficult than keeping awake people who are not depressed.

Prolonged loss of sleep can lead to temporary impairment of judgment comparable to that induced by consuming several ounces of alcohol.

The dramatic shifts in mood connected with sleep and wakefulness have not been traced to particular changes in brain chemistry.

Depression returns in full force as soon as the patient sleeps for even a few minutes.