Associations Between Youth Marijuana and Alcohol Use, Neurocognitive Performance, and Triple-Network Resting-State...

Adolescent substance use is associated with increased risk of suicide, overdose, and executive dysfunction. Alcohol and marijuana are the two most-used substances among young people. Substance use is associated with dysfunctional resting-state network connectivity between the default mode network (DMN), executive control network (ECN), and salience network (SN) and executive dysfunction. There is limited research on triple-network connectivity (DMN, ECN, SN) in adolescents who use substances.

In typically developing youth from the Philadelphia Neurodevelopmental Cohort (PNC), regression models were used to examine relationships between alcohol and marijuana use and triple-network connectivity (n = 520), while adjusting for age, sex, maternal education, and head motion. In individuals with neurocognitive and substance use data (n = 4197), regression models were used to examine relationships with executive control.

Alcohol use was not associated with any connectivity measures after false discovery rate correction. Higher marijuana use was associated with higher DMN-ECN connectivity (F_2,507 = 5.08, p = .0066, q = .039). Higher alcohol use was associated with better working memory (p = .020), mental flexibility (p < .0001), attention (p = .019), and executive efficiency (p = .0015) and accuracy (p = .00044), which may have been due to other socioeconomic factors. Marijuana use was not associated with neurocognitive performance.

In typically developing youth, marijuana use was associated with DMN-ECN connectivity, while alcohol use was associated with neurocognitive performance. Future research should use interventions targeting the DMN, ECN, and SN to interrogate relationships between connectivity, cognitive performance, and substance use.