Sleep Delta power, age, and sex effects in treatment-resistant depression

Electroencephalographic (EEG) deficits in slow wave activity or Delta power (0.5–4 Hz) indicate disturbed sleep homeostasis and are hallmarks of depression. Sleep homeostasis is linked to restorative sleep and potential antidepressant response via non-rapid eye movement (NREM) slow wave sleep (SWS) during which neurons undergo essential repair and rejuvenation. Decreased Low Delta power (0.5–2 Hz) was previously reported in individuals with depression. This study investigated power levels in the Low Delta (0.5-2 Hz) Delta bands were compared in NREM1-3.•In NREM1, TRD participants had reduced Delta power versus healthy volunteers (HVs).•This difference was mostly due to Low Delta (0.5-40y) had higher Low Delta than older males (>40y).