Dr. Milin is associate professor and clinician investigator in the Department of Psychiatry at the University of Ottawa. He is director of the Adolescent Day Treatment Unit in the Youth Psychiatry Program, and was the founding clinical director of the Youth Program at the Royal Ottawa Mental Health Centre (ROMHC). He is the psychiatric and research consultant with the David Smith Youth Treatment Centre, a provincial residential centre for youth addiction treatment. He is a member of the Institute of Mental Health Research, at ROMHC at the University of Ottawa; and is involved in ongoing research in the areas of youth mental health, substance use, and concurrent psychiatric disorders. He has authored and co-authored numerous publications on substance use disorders, and the treatment and phenomenology of youth psychiatric disorders. Dr. Milin is an experienced clinician and researcher with expertise in youth psychiatry, addictions, and early-onset major psychiatric disorders. In this CCB, he discusses the impact of adolescent substance abuse, primarily cannabis, on the development, assessment, course, and treatment of comorbid psychiatric disorders.