[The effect of an increased intensity of light on changes in the serotonin and melatonin content in patients with depression].

Study into the effect of light of increased intensity shows that in patients with anxious depression a high level of melatonin excretion declines to normal, its low level in melancholic depression remaining unchanged. Blood concentrations of serotonin in depressive patients are higher as compared with the healthy persons and do not change with increasing in the brightness of the illumination except for a decrease in a portion of patients showing maximum levels of serotonin and melanin.