Chronotype, Longitudinal Volumetric Brain Variations Throughout Adolescence, and Depressive Symptom Development

Area of Science:

• Neuroscience
• Developmental Psychology
• Genetics

Background:

• Adolescence is a critical period for circadian rhythm development, marked by a shift towards eveningness around age 14.
• Eveningness in adolescents is associated with an increased risk for later depressive symptoms.
• Previous research has not explored the link between early adolescent chronotype, brain structure, and the development of depressive symptoms.

Purpose of the Study:

• To investigate structural brain variations associated with chronotype in early adolescence.
• To examine how these variations relate to the development of depressive symptoms.
• To assess the role of genetic factors in mediating or moderating these associations.

Main Methods:

• Longitudinal assessment of 128 adolescents from age 14 to 19.
• Voxel-based morphometry to analyze regional gray matter volumes (GMVs) at baseline and follow-up.
• Correlation of GMVs with chronotype (Morningness/Eveningness Scale), sleep habits, and depressive symptoms, considering genetic factors (COMT Val/Val).

Main Results:

• Higher eveningness correlated with larger GMV in the right medial prefrontal cortex at ages 14 and 19.
• GMV in the medial prefrontal cortex was associated with depressive symptoms at age 19 in COMT Val/Val carriers.
• Larger GMV in the right fusiform gyrus at age 14 was linked to weekend later wake-up times.

Conclusions:

• Eveningness and associated sleep habits in adolescence show distinct developmental patterns.
• Medial prefrontal cortex GMV changes linked to eveningness may represent a vulnerability factor for depressive symptoms in COMT Val/Val carriers.
• These findings highlight the interplay between chronotype, brain development, and mental health during adolescence.