Subjective Sleep Timing and Social Jet Lag Relate to Neural Activation During Reward Feedback in Adolescence

During adolescence, circadian phase delay yields later sleep timing and greater social jetlag (SJL), coinciding with heightened reward-circuit reactivity as subcortical systems mature before prefrontal control. Evidence linking sleep timing to reward-related neural activation in youth is limited. We examined whether sleep timing and SJL are associated with neural activation during reward processing in adolescents. In individuals with fMRI data, mid-sleep on free days (MSFsc) and SJL were derived from the Munich Chronotype Questionnaire (MCTQ; n = 5678) and Fitbit data (n = 2245) in adolescents (10-13 years) from the ABCD dataset. Reward processing was assessed using the fMRI Monetary Incentive Delay task, dissociating anticipation (reward/loss vs. neutral) and feedback (hit vs. miss). Linear mixed-effects models relate BOLD activation in a priori regions (amygdala, striatum, orbitofrontal cortex [OFC], insula, cingulate and frontal subregions) to sleep metrics. Later self-reported MSFsc was associated with greater activation during reward receipt in the left amygdala and right lateral OFC (β = 0.05-0.06, p_fdr < 0.05). The OFC association persisted after adjustment for sleep duration, while the amygdala effect was attenuated. Higher self-reported SJL also predicted increased left amygdala activation during reward receipt (β = 0.05, p_fdr < 0.05). Fitbit-derived MSFsc and SJL were not associated with reward-related activation after correction for multiple comparisons. Self-reported later sleep timing and greater SJL were linked to heightened affective and regulatory neural responses during reward-feedback. The divergence between self-reported and Fitbit-derived findings suggests that subjective and objective sleep timing measures may capture distinct aspects of sleep timing with relevance for neural reward outcomes. Sleep timing, beyond duration, represents a modifiable target for improving adolescent circadian health.