2019

What we knew about this subject

• Cortisol reactivity is a frequently studied biomarker of substance use, although not often studied in adolescence.
• Previous research shows that other developmental influences, including genetic and prenatal and postnatal environmental factors, contribute to cortisol reactivity and to the use of drugs for adolescents
• The relative contribution of these factors is unknown

What this study adds
The present study tested a comprehensive developmental model that included the combined influence of many genes, prenatal stress, parenting, and emotional/behavioral problems on both cortisol reactivity and substance use outcomes in adolescence. Although we expected stress hormone reactivity to be a key factor leading to adolescent substance use, we found little evidence of this. Instead, we found that influences that occur earlier in development – prenatal stress and colder parenting – are important for understanding how emotional and behavioral problems independently relate to both cortisol reactivity and substance use. We found a strong pathway of development to drinking, smoking, and marijuana use was from prenatal stress and colder parenting through externalizing problems. We further found was some evidence of protective effects of internalizing problems (for example, anxiety and depressive symptoms) leading to less marijuana and alcohol use. Our findings thus confirm the key role that externalizing problems play in the development of substance use, but also suggest a need to take into account a broader developmental context for understanding the relationship of internalizing problems with adolescent substance use.