OBJECTIVE:

Although several treatments for adolescent substance abuse have been identified as promising by reviewers and federal agencies, treatment effects extending beyond 12 months have not been demonstrated in randomized clinical trials. The primary purpose of this report was to examine the 4-year outcomes of an evidence-based treatment of substance-abusing juvenile offenders.

METHOD:

Eighty of 118 substance-abusing juvenile offenders participated in a follow-up 4 years after taking part in a randomized clinical trial comparing multisystemic therapy (MST) with usual community services. A multimethod (self-report, biological, and archival measures) assessment battery was used to measure the criminal behavior, illicit drug use, and psychiatric symptoms of the participating young adults.

RESULTS:

Analyses demonstrated significant long-term treatment effects for aggressive criminal activity (0.15 versus 0.57 convictions per year) but not for property crimes. Findings for illicit drug use were mixed, with biological measures indicating significantly higher rates of marijuana abstinence for MST participants (55% versus 28% of young adults). Long-term treatment effects were not observed for psychiatric symptoms.

CONCLUSIONS:

Findings provide some support for the long-term effectiveness of an evidenced-based family-oriented treatment of substance-abusing juvenile offenders. The clinical, research, and policy implications of these findings are noted.