Research on adolescent marijuana use has given insufficient attention to understanding the functions of marijuana in youngsters' overall adaptation, and particularly in the context of family psychodynamics. This research focused on 17 marijuana-abusing adolescents who were selected according to the“representative case method.”Data obtained through unstructured psychodynamic interviews with the youngsters and their families were analyzed to identify the functions which marijuana played for these adolescents. Five key functions related to family psychodynamics-defiance and provocation, self-destructiveness, control of anger, grandiosity, and escape from competitive conflicts-are described. A case illustration is presented to show how these functions are interrelated in the adolescents' adaptation.