The sleep EEG and nocturnal hormonal secretion studies on changes during the course of depression and on effects of CNS-active drugs.

1. The sleep EEG and nocturnal hormone secretion were studied simultaneously in normal male controls and in male patients with major endogenous depression before treatment with tricyclics and after recovery and drug cessation. 2. Several studies were performed in normal male controls to investigate the effect of antidepressants (brofaromine, moclobemide, amitriptyline, clomipramine and trimipramine) and of neuropeptides (CRH and the ACTH (4-9) fragment analog ebiratide) on the sleep EEG and sleep-associated hormone secretion. 3. Elevated cortisol and blunted testosterone secretion are state markers of acute depression, whereas sleep EEG, GH and prolactin variables do not show marked differences between acute depression and recovery. Except for trimipramine, all antidepressants investigated suppress REM sleep. No systematic relationship between the sleep EEG and endocrine effects of antidepressants is detectable. Pulsatile application of CRH in controls mimicks some of the neurobiological symptoms of acute depression. More shallow sleep occurs under ebiratide, whereas hormonal secretion remains unchanged. 4. Our data demonstrate that antidepressants exert distinct effects on sleep. However, these substances do not induce changes in sleep structure which persist after their withdrawal in remitted patients. Pulsatile application of neuropeptides leads to specific effects on CNS activity which are not mediated by changes of peripheral hormone secretion. The view that CRH plays a key role in the pathophysiology of affective disorders is corroborated.