Addictive disorders in youth represent a dynamic field characterized by shifting patterns of substance use and high rates of experimentation, while retaining the risky behaviors and negative outcomes associated with established drug classes. Youth/adolescents are also at the forefront of use of new technologies, and non–substance-related disorders are pertinent. These disorders present with similar pictures of impairment, and can be diagnosed following the same principles. An underlying mental disorder and the possibility of a dual diagnosis need to be assessed carefully, and optimal treatment includes psychosocial treatments with applicable pharmacologic management, the latter representing an expanding field.