|Beitragstitel||Slow wave activity in adolescents with major depressive disorder|
Depression is often accompanied by sleep complaints, including difficulty falling or staying asleep, or waking up too early. In adolescents as well as adults with major depressive disorder (MDD), studies have found changes in slow wave activity (SWA). Due to samples with broad age ranges, different medication status’ and variable severity of depression, findings have been inconclusive. The aim of the present study was to examine sleep neurophysiology in an un-medicated sample of adolescents with and without major depressive disorder (MDD) using high-density sleep electroencephalogram (EEG).
Thirty-nine adolescents with and without depression between the age of 14 and 17 years (mean 15.15 years, SD = 1.1; 25 females; 18 with MDD) participated in the present study. Based on a clinical interview, participants were screened for MDD. The three days before the high-density sleep EEG (58 EEG derivations) was recorded, participants followed a sleep schedule ensuring at least 9 hours of time in bed. An ANOVA with factors age, sex and group was used to determine significant differences between the groups and slow wave activity (SWA) was calculated as power in the 0.6-4.6 Hz range.
In our study, we found a significant diminution of SWA in adolescents suffering from depression as compared to those without depression. Thirty-three derivations distributed over widespread brain regions showed statistically significant reduction in SWA in the MDD group. Effect sizes were large, with eta-squared values for significant electrodes ranging between 0.11 to 0.28.
The reduction of SWA in adolescents with MDD as compared to controls was topographically more widespread and effect sized were larger compared to previous studies in adolescents. This might be explained by the recruitment of an un-medicated sample, the narrow age range and the moderate to severe depression, which may help reduce variability and furthermore, increases statistical power. Our results add to the existing literature showing a reduction of SWA in MDD and further our understanding of the role of sleep in adolescent depression.