The comparison of polysomnographic data between a group of nine major depressive adolescents, 12 minor depressive adolescents and 12 controls showed a significant difference in sleep efficiency index and in percentage of awakenings. Sleep efficiency was reduced in major depressive adolescents and the percentage of awakenings was increased. Pubertal stage did not appear to have any effect on sleep EEG recordings. The administration of dexamethasone provoked a suppression of cortisol secretion in 50% of major depressive adolescents. Pubertal stage did not appear to have any significant effect on cortisol level after DST.