Mechanisms of Depression and Anhedonia in Adolescents: Linking Sleep to Reward- and Stress-Related Brain Function

Participants in the sleep extension and advance condition will maintain a stable sleep schedule that extends sleep duration and advances bedtime by 90 min relative to weekday bedtime. This chronotherapeutic manipulation will include blocking phase-delaying light in the evening using goggles with orange lenses ("blue blockers") beginning 2 h prior to bedtime, and 30 min of 506 lux blue-green light exposure in the morning beginning at rise time using bright light goggles (ReTimer Pty Ltd., Australia). Schedule and chronotherapy adherence will be reinforced using motivational techniques (e.g., securing motivation, preplanning, problem-solving), requiring participants to text the study coordinator and complete morning assessments at rise time, and monetary incentives.

Participants in the regular sleep duration and timing condition will keep a stable sleep schedule that matches their typical weekday sleep opportunity and timing. Schedule adherence will be reinforced using motivational techniques (e.g., securing motivation, preplanning, problem-solving), requiring participants to text the study coordinator and complete morning assessments at rise time, and monetary incentives.