Simultaneous study of 24-hour patterns of melatonin and cortisol secretion in depressed patients

The temporal organization of melatonin and cortisol secretion were studied in depressed patients in order to investigate a possible relationship between the secretory patterns of the two hormones. Women who suffered from a primary affective disorder were studied twice as inpatients, the first time during the depressive episode and the second time after amitriptyline treatment and clinical recovery. During both 24-hour studies blood was collected at 1-hour intervals during the day and at 30-min intervals at night. A dissociation of melatonin and cortisol secretory patterns was observed in the 3 patients in whom the two hormones were determined simultaneously. 2 patients exhibited alterations in the circadian rhythm of both hormones during illness. After recovery, however, the melatonin rhythm remained altered but the cortisol rhythm was normalized. Another patient showed a nocturnal melatonin rise and day-night melatonin differences closer to those seen in normal subjects, but she had altered cortisol secretory patterns during depression which normalized after recovery. These results suggest that the melatonin and cortisol rhythms are controlled by different mechanisms.