Differences in nocturnal melatonin secretion between melancholic depressed patients and control subjects.

The authors took multiple serum samples for measurement of melatonin between 4:30 p.m. and 7:30 a.m. in seven male depressed patients with melancholia and five healthy male control subjects and found that melancholic patients had a significantly lower rise of melatonin. They also compared a second, separate group of 14 women and five men suffering from melancholic depression with seven healthy male control subjects and nine depressed women without melancholia. The melancholic patients had a significantly lower concentration of serum melatonin at 11:00 p.m. than either the control subjects or the nonmelancholic depressed patients. These findings support the possibility that the functioning of the pineal gland is altered in these patients.