Adolescent substance use trajectories are associated with nucleus accumbens functional connectivity

Adolescent substance use is associated with disrupted communication among brain regions underlying reward-driven behaviors (e.g., nucleus accumbens (NAcc)) and cognitive/emotional control (e.g., prefrontal cortex (PFC); medial temporal lobe), which may be linked to poor future outcomes (e.g., substance use disorder). However, the relationship functional brain connectivity has with trajectories of adolescent alcohol, tobacco, and cannabis use has received limited attention.

Investigate relationships between adolescent substance use trajectories and young adult whole-brain NAcc resting-state functional connectivity (rsFC).

Substance use was assessed at ages 11, 13, 16, and 19. Subsequently (age 20), a subset of participants (N = 299) completed a single neuroimaging session. Latent growth curve models estimated substance use trajectories that included the intercept (age 14 use), linear slope (progression), and quadratic slope (acceleration), which served as predictors in neuroimaging analyses.

Substance use trajectories representing greater age 14 usage, faster progression of use, and acceleration of use across adolescence would show stronger NAcc rsFC with regions implicated in cognitive/emotional control.

Age 14 use (alcohol, tobacco, and cannabis) was associated with NAcc rsFC with dorsolateral PFC, dorsomedial PFC, parahippocampal gyrus (PHG), hippocampus, and amygdala. Progression of use was associated with NAcc rsFC with dorsolateral PFC, dorsomedial PFC, ventrolateral PFC, PHG, and amygdala. Finally, acceleration of use was linked with NAcc rsFC with dorsolateral PFC, ventromedial PFC, PHG, and hippocampus.

NAcc rsFC with several brain regions (e.g., PFC subregions) varied with adolescent substance use, which may represent common neural mechanisms linking adolescent substance use with common psychological outcomes.