Abstract: Comparison of the two therapies found that a year after treatment, teen participants in the MDFT group had fewer drug-related problems and showed more improvement on general measures of behavior and mental health than those teens treated with cognitive-behavioral therapy (CBT). The therapies were compared in two randomized trials sponsored by the National Institute on Drug Abuse. The first study included 224 juvenile males, predominantly African-American, average age of 15 years, and from low-income, single-parent homes, who received either MDFT or CBT. Among the participants, 75 percent were diagnosed as cannabis dependent, 20 percent were alcohol dependent, and 13 percent were dependent on other substances. The study found that while both treatments were effective at discharge, in the months following treatment, youth who received MDFT had lower scores on the Personal Experience Inventory, which measures impairment due to personal, social, educational, and legal problems tied to drug abuse, than those youth who received CBT. The second study tested the effectiveness of MDFT versus CBT in a younger group of adolescent substance abusers, average age of 13.5 years. The results of this study were similar to those of the first study, in that both MDFT and CBT were effective at discharge, but those youth who received MDFT experienced longer lasting gains than the CBT youth. The MDFT youth had significantly lower levels of drug use, had improved their academic performance, had fewer arrests and placements on probation, suffered fewer psychiatric symptoms, and reduced self-reported delinquency and their association with delinquent peers. Issues for future research are discussed.