Cognitive and behavioral pathways from prenatal cocaine exposure to regular marijuana use during emerging adulthood.

Objective: This study considers indirect effects of 12-year global executive function, externalizing behavior (EXT), perceptional reasoning IQ (PRIQ), and 15-year substance use on the relationship between prenatal cocaine exposure (PCE) and regular marijuana use at 21 years.

Methods: Participants were 310 (154 PCE, 156 non-prenatally cocaine-exposed (NCE) enrolled at birth. Regular marijuana use at age 21 (> 1-7 times/week) was assessed using the Substance Abuse Module 5 (SAM 5). Caregiver reports of executive function via the Behavior Rating Inventory of Executive Function, Global Executive Composite (GEC), Wechsler perceptual reasoning (PRIQ), Child Behavior Checklist youth-reported EXT were assessed at 12 years, and substance use at 15 years. Structural equation modeling evaluated GEC, PRIQ, EXT, and substance use as mediators linking PCE to regular marijuana use, adjusting for qualifying prenatal drug exposures (tobacco) and adverse environmental conditions.

Results: Emerging adults with PCE reported higher rates of regular marijuana use than those with NCE (50.7 % vs. 39.4 %, p = .046). PCE was related to poorer GEC at age 12 (β = 0.19, p < .001), which in turn was related to substance use at age 15 (β = 0.21, p = .002), which was related to regular marijuana use at age 21 (β = 0.70, p < .001), yielding an indirect effect of PCE (β = 0.028, p = .032). EXT was not related to 15-year substance use or 21-year marijuana use.

Conclusions: Efforts to examine and address early cognitive and behavioral patterns could prevent regular marijuana use among emerging adults with PCE.