Social Environmental Factors Help to Explain Early Substance Use Initiation Among Youth With Comorbid Psychological...

To examine how substance use (SU) initiation during early adolescence is influenced by youths' comorbid psychological and somatic symptom trajectory (C-PSST), risk perceptions, and their proximal environment.

Using Adolescent Brain Cognitive Development longitudinal study data, we classified youth into asymptomatic/low versus moderate/high C-PSST groups. The outcome, SU initiation, was derived from biannual youth reports. Youths' risk perceptions, family (parent SU problem, monitoring, SU rules) and peer factors (perceived peer disapproval and SU) were recorded annually. Cox regression determined hazard rates with 95% confidence intervals for factor and interaction effects.

Among our sample of 9,848 youths, those in the moderate/high C-PSST group had a 56% higher rate of SU initiation than the asymptomatic/low C-PSST group. However, the effect of symptom group became nonsignificant when family and peer factors were considered. Higher parental monitoring, peer disapproval, and youths' risk perceptions independently decreased the risk of SU initiation, while lax parental rules and any perceived peer use increased the risk. Youth in the moderate/high C-PSST group were at 42% higher risk of SU initiation only when their parents reported a SU problem (HR 1.42 [95% CI 1.01-2.00]).

Our findings show how youths' comorbid symptomology and environmental factors impact SU initiation during early adolescence. The higher SU initiation rate among youth with moderate/high C-PSST was moderated by environmental factors. Thus, in addition to managing comorbid symptomology, strategies to address environmental risk factors may be needed to decrease early SU initiation for vulnerable youth.