DESCRIPTION: (Applicant's Abstract) The proposed study is designed to evaluate the effectiveness of a brief intervention tailored for adult chronic marijuana users who have neither self-initiated efforts to change nor sought treatment. Earlier research has demonstrated that "The Marijuana Check-Up," a two-session intervention publicized as not treatment, but rather an in-depth opportunity to explore one's marijuana use history and consequences, successfully reached and enrolled adult chronic marijuana smokers with multiple problems associated with their use. Post-intervention data collected from these individuals supported the efficacy of the intervention in promoting behavioral change. In the currently proposed trial, the efficacy of an augmented Marijuana Check-Up will be compared with the intervention previously tested. Participants randomized to the augmented Marijuana Check-Up condition will be invited to meet with a counselor for four additional sessions over the following 12-week period. The content of these sessions, motivational enhancement therapy and/or cognitive-behavioral therapy, will be matched to the participant's level of readiness for change. All participants will be followed-up for one year following enrollment.