The role of sleep and wakefulness in the genesis of depression and mania.
Disturbances of the sleep-wake cycle are frequently seen in affective illness and are exhibited in other psychiatric illness as well. In addition to being a useful research probe, manipulations of the sleep-wake cycle such as sleep deprivation (SD) and phase advance can cause depression to remit and thus can be used as alternative or as adjunctive to pharmacologic treatment. The antidepressant response to SD occurs whether antidepressant drugs are administered or not. However, there is some evidence that the concomitant use of antidepressants may prevent the relapses that occur after recovery sleep. Data from clinical investigations also indicate that disrupted sleep can trigger and intensify mania. Rapid cycling bipolar patients may be especially vulnerable to mania/hypomania after disrupted sleep or SD. Characteristic changes in body temperature have been recorded in sleep deprivation as well as in other antidepressant treatment modalities. Thermoregulatory physiology may therefore provide a framework for understanding the effects of sleep-wake manipulations in affective illness.