Sleep and Circadian Markers for Depression in Adolescence

Early-onset major depressive disorder (MDD) is associated with significant morbidity in adolescence. The interview-dependent diagnostic process used in psychiatry leaves a subset of adolescents with MDD undiagnosed. Sleep disturbances are a central feature of depression and adolescence is a period of rapid change in sleep physiology. The aim of this study was to test physiological features of sleep and circadian rhythms as markers of adolescent MDD. Adolescents completed a two-week protocol that included a formal psychiatric interview, polysomnographic (PSG) assessment, actigraphy, salivary melatonin sampling, and holter monitoring. Depressed adolescents (n = 18) differed from controls (n = 15) on features of sleep macroarchitecture measured by PSG, and on autonomic nervous system functioning measured by 24-hour heart rate variability. Depressed adolescents had shorter REM latency and decreased stage 4 sleep. Adolescents with MDD also showed decreased parasympathetic activity over 24-hours and during the day, and decreased sympathetic activity during the night.MAS