Sleep and the Daytime Course of Anhedonia in Adolescent Depression: An Ecological Momentary Assessment Study

Background: Mounting evidence suggests that sleep disturbances and depression are linked through disruptions in reward processing. This pathway may be especially relevant to adolescent depression, as adolescence is characterized by more frequent sleep disturbances, reduced sleep, and refinement of reward circuitry.Aim: This preregistered study uses high-density ecological momentary assessment (EMA) data from the Characterization and Treatment of Adolescent Depression Studies (CTADS) cohort (collected from 2023 to 2026) to test sleep disturbances and duration as predictors of anticipatory and consummatory anhedonia and to determine whether effects exhibit diurnal variation.Methods: Sixty-five adolescents (12-18 years; 43 female, 22 male; 41 with major depressive disorder, 24 healthy volunteers) completed 120 EMA prompts over 30 days. Participants reported prior-night sleep disturbances and duration once per day, and anticipatory and consummatory anhedonia four times per day. We ran two Bayesian multilevel linear models, estimating anticipatory and consummatory anhedonia, respectively, as functions of prior-night sleep disturbances, time of day, diagnostic group, and their interactions. We then ran two exploratory models assessing sleep duration in the same manner.Results: In adolescents with MDD, whereas self-reported sleep disturbances did not predict anhedonia, longer sleep duration predicted both lower anticipatory and lower consummatory anhedonia. In healthy adolescents, greater sleep disturbances predicted lower anticipatory and lower consummatory anhedonia. Effects of sleep disturbances on anhedonia tended to increase across the day in adolescents with MDD and healthy adolescents.Conclusions: Sleep disturbances and duration differentially predict next-day anhedonia in adolescents with MDD. For adolescent MDD patients, treatments that target sleep duration, as opposed to sleep disturbances, could provide more immediate effects on anhedonia. Time-of-day moderation effects suggest the mechanisms through which sleep disturbances (but not sleep duration) affect anhedonia may involve diurnal biological processes.