During the past quarter century, marijuana use by young people has evolved from an uncommon behavior to the current situation where marijuana is the most common illicit drug chosen by teen-agers. Among high school seniors in the United States over half have used marijuana at least once. Approximately one fourth of these seniors reported use during the prior month, with some 4 percent reporting daily use. Marijuana use often begins early in adolescence with over 25 percent of all teenagers reporting that they used the drug prior to entrance into the tenth grade.1 This statement is an update of a previous statement written by the American Academy of Pediatrics on marijuana use2 and is an adjunct to the Academy's statement on "The Role of the Pediatrician in Substance Abuse Counseling."3
