Sex and age differences in brain metabolism and cognition in adolescents.

Adolescence is a period of neural development, marked by maturation of brain structure and function. While sex- and age-related markers of structural brain development are documented, neurochemical and cognitive changes are less understood. Our goal was to evaluate neurochemistry and cognition in adolescents as a function of sex and age. Magnetic resonance spectroscopy quantified brain metabolites, and attention networking, digital trail making, and cued task switching tests measured cognition in 354 healthy adolescents. Groupwise comparisons and linear regressions evaluated sex- and age-related effects, respectively. Males were differentiated from females in cognitive performance and brain metabolite concentrations, including myo-inositol, glutamate + glutamine (Glx), N-acetylaspartate, and creatine. Males performed tasks with faster speed while females demonstrated better accuracy. Decreases in Glx concentration and faster reaction times were associated with increasing age, indicative of maturing brain function during adolescence. These findings highlight adolescence as a period of active brain development.