Association between nucleus accumbens volume and future tobacco and Marijuana use in early adolescence

Abstract

IntroductionNucleus accumbens (NAc), a crucial component of the brain's reward network, plays a role in reward-related behaviors like substance use. However, limited knowledge exists about sex differences in the predictive power of NAc volume for the initiation of tobacco and marijuana use among children transitioning into early and middle adolescence. Our aim was to compare the predictive utility of NAc volume for adolescents' initiation of tobacco and marijuana use over a three-year period. MethodsData from the Adolescent Brain Cognitive Development study (ABCD), a longitudinal study of pre-adolescents aged 9–10 years, were utilized. The study included 9–10 pre-adolescents (n = 11,795) who were followed for 36 months. Cox regression was employed to examine whether NAc volume predicts subsequent initiation of tobacco and marijuana during the follow-up period. Covariates included age, race/ethnicity, puberty, parental composition, parental education, and area-level median income. Sex was the moderator. ResultsWhile NAc volume predicted future substance use, this association varied based on substance type (tobacco vs. marijuana), sex (male vs. female), and laterality (brain hemisphere). A larger right NAc volume (mm^3) inversely associated with subsequent tobacco use initiation for female youth (HR = 0.998; 95% CI: 0.996–1.000), while it showed no association for male youth (p = 0.385). Larger left NAc volume (mm^3) did not associate with subsequent tobacco use initiation for female youth (p = 0.108) but showed a positive association for male youth (HR = 1.002; 95% CI: 1.001–1.003). NAc volume did not show an association with subsequent marijuana use initiation for either sex. ConclusionsThe predictive impact of right and left NAc volumes on future tobacco or marijuana use may differ for male and female adolescents, suggesting that the salience of NAcc in regulating the reward system is influenced by sex, substance type, and brain hemisphere.