Sleep as a moderator of adolescent brain development - evidence from a longitudinal MRI study.

Study Objectives Adolescent brain maturation is characterized by profound structural changes to grey and white matter. While cross-sectional studies in youth indicate that measures such as sleep duration and regularity are linked to regional grey matter volumes, there is less evidence on how sleep may shape developmental trajectories over time. Therefore, the goal of this study was to test whether objectively measured sleep is a moderator of grey matter volume changes in early adolescence. Methods Structural MRI was acquired longitudinally at two time points six months apart in 39 healthy adolescents aged 10 to 14 years (mean age = 12.72 ± 1.00 years). Between the two MRI scans, we collected daily objective sleep/wake behavior using actigraphy (mean = 129.95 ± 34.01 nights). We then examined how sleep duration, efficiency, timing, and regularity moderate changes in seven regions-of-interest (ROIs) linked to social/emotional functioning using univariate simple moderation models for each ROI and sleep characteristic. Results Sleep duration and efficiency moderated grey matter volume changes in regions including the thalamus, precuneus, orbitofrontal cortex, and amygdala (.11 ≤ ΔR2 ≥ .50; .001 < p<.020). Shorter and more disrupted sleep was associated with attenuated structural changes. Sleep regularity and sleep midpoint further moderated changes in grey matter volume (.05 ≤ ΔR2 ≥ .30, .001 < p<.043), indicating a role for these parameters in brain development. Conclusion These findings highlight the potential role of sleep in adolescent neurodevelopment and underscore the potential for targeted interventions to support brain health during this critical window.