Rapid eye movement sleep and sleep continuity. Depression and antidepressants.

Abnormalities of sleep and mood occur in depressive illness, and both disturbances may respond to therapy. Antidepressant drugs of all classes bring about immediate and often pronounced changes in sleep. Some drugs reduce, whereas others increase, nocturnal wakefulness, but most, if not all, suppress rapid eye movement activity, although it is uncertain whether this is linked directly to elevation of mood. Such changes in sleep continuity are related to the individual pharmacological profile of drugs, and in some instances, such as with trimipramine, may arise from the interaction of properties which alone may not lead to marked effects on sleep. On the other hand, inhibition of REM sleep appears to be related to a nonspecific disturbance of the balance between monoaminergic and cholinergic influences. In this way, REM sleep is reduced not only with drugs which selectively modulate noradrenaline or serotonin activity, but also with drugs which have complex pharmacological profiles.