Diurnal mood variation in major depressive disorder.

TLDR

Depression disrupts mood, yet the pattern of diurnal mood rhythms in depression remains unclear. The study examined how positive affect and negative affect vary diurnally in depressed versus healthy individuals. Participants completed repeated experience sampling of PA and NA over six days, with 47 depressed outpatients and 39 healthy controls. Depressed participants showed a later peak and rising positive affect during the day, while their negative affect displayed a stronger diurnal rhythm and greater moment‑to‑moment variability compared to healthy controls, indicating distinct diurnal disturbances of positive and negative affect.

Abstract

Depression disturbs mood, but a clear picture of diurnal mood rhythms in depression has yet to emerge. This study examined variations in positive affect (PA) and negative affect (NA), two dimensions of mood that generate diurnal patterns among healthy individuals. Repeated measurements of NA and PA in daily life were obtained over 6 days from 47 depressed outpatients and 39 healthy individuals using the Experience Sampling Method. Relative to healthy individuals, depressed individuals exhibited increasing PA levels during the day with a later acrophase. In contrast, depressed persons' NA exhibited a more pronounced diurnal rhythm and was more variable from moment to moment than healthy individuals'. Ambulatory mood measurements in depression suggest distinct diurnal disturbances of positive and negative affect.