Dr. James Berry highlights the three most common substances adolescents tend to misuse: alcohol, tobacco, and cannabis (marijuana). He notes that while public health efforts have reduced tobacco use, vaping nicotine has surged among young people, becoming a major concern. Cannabis use is also increasing, especially as more states legalize it, leading to a perception of safety. Alcohol, being culturally accepted, remains the most common substance children first encounter. Dr. Berry emphasizes the importance of parents modeling healthy behaviors to help prevent substance use in their children.