Reduction of Sleep Spindles in Children and Adolescents with Major Depression is Age and Sex-Dependent

Background: Major Depressive Disorder (MDD) is associated to substantial sleep disturbances and reduced neuroplasticity. Sleep spindles, involved in neuroplasticity mechanisms during brain development, are more abundant in children and adolescents than in adults, and as such, might be a sensitive measure of sleep alterations in early-onset MDD. This study investigated the effects of sex and age on sleep spindles in children and adolescents with MDD. Methods: The study included 69 depressed [34 children 8-12 years of age (18 males and 16 females) and 35 adolescents 13-18 years of age (14 males and 21 females)], and 42 healthy [18 children 8-12 years of age (10 males and 8 females) and 24 adolescents 13-18 years of age (12 males and 12 females)] youth. All participants maintained a regular sleepwake schedule for 5 days followed by two consecutive nights in the laboratory. Spindle density (SD) was analyzed in Stage 2 of non-rapid eye movement sleep. Results: Children and adolescents with MDD showed lower SD than healthy controls (p