Associations Between Sleep and Cortical Thickness Asymmetry in Late Adolescence and Early Adulthood

Sleep quality is associated with brain development and cognition; however, its relationship with hemispheric cortical organization during late adolescence and early adulthood remains unclear. We examined the associations among subjective sleep quality, cortical thickness asymmetry, and fluid cognition in 100 participants using cross-sectional data from the Human Connectome Project–Development (aged 19.98 ± 1.15 years; 53% female). Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI) and cortical thickness lateralization indices (LIs) calculated for 34 homologous cortical regions. Regression models were adjusted for age, sex, body mass index, handedness score, education level, and global mean LI, with false discovery rate (FDR) correction. Poor sleepers had lower LIs in the entorhinal, medial orbitofrontal, parahippocampal, and insular cortices and the frontal and temporal poles (all FDR-corrected p < 0.05). Higher PSQI scores were associated with lower LIs in the entorhinal cortex, temporal pole, and insula (all FDR-corrected p < 0.05). No LI–fluid cognition associations were maintained after FDR correction. In a post hoc exploratory mediation analysis, a significant indirect effect on the entorhinal LI (β [95% confidence interval] = −0.705 [−0.873, −0.411], p = 0.006) was observed. These findings suggest that subjective sleep quality is associated with region-specific differences in cortical thickness asymmetry.