[Melatonin excretion in patients with depression under the action of light of increased intensity]

The effects of 1 and 10 bright light exposures (2600-8000 lux) on melatonin excretion in patients with melancholic and anxious depressions were examined. Before treatment the increased basic levels of melatonin excretion were observed in patients with anxious depression. Melatonin excretion had been gradually normalized after 1 and 10 sessions of light therapy. The basic melatonin excretion in melancholic depressed patients was low and hadn't been changed after light therapy. Long term effects of light therapy depend upon the initial levels of melatonin excretion: low pretreatment levels increased and high pretreatment levels decreased after the therapy. The authors proposed that bright light exposures stimulated the restoration of adaptive function of pineal gland in depressed patients.