Abstract
Adolescence is characterized by ongoing neurodevelopment and psychosocial development, resulting in a unique window to the adverse effects of traumatic events and substance use. In addition, trauma- and stressor-related disorders and substance use disorders (SUDs) commonly co-occur in adolescents. Youth with interpersonal violence and who have experienced multiple past traumas, or poly-victimization, are at the highest risk of developing these co-occurring disorders. There is a strong bidirectional relationship between traumatic events and substance use that predisposes youth to developing post-traumatic stress symptoms (PTSS) and SUDs. PTSD and states of substance intoxication and withdrawal also exhibit overlap in symptomatology. High rates of comorbidity may be explained in part by the self-medication hypothesis, that posits that individuals use substances to temporarily alleviate trauma-related symptoms. However, this results in negative reinforcement, often with increasing patterns of substance use and worsening symptoms of hyperarousal, dysphoria, and anxiety. In addition, PTSS and substance use problems share common risk factors and neurobiologic etiology, conceptualized as the susceptibility hypothesis. Youth who experience traumatic events and/or have substance use problems access the healthcare system at multiple levels, including through acute care and crisis services. Notably, substance use in adolescence increases the likelihood of experiencing a traumatic event, and youth presenting to the emergency department for substance-related problems are at higher risk of having a PTSD. Youth presenting for mental health, behavioral, or substance-related problems should be screened for PTSS and substance use problems. Given the strong clinical overlap and bidirectional relationship, evidence-based treatment integrates management of both disorders. An interdisciplinary approach with psychotherapy, psychopharmacologic therapy, and case management is often vital to engaging and maintaining youth in treatment.