What is this review about?
Multisystemic Therapy® (MST) is an intensive, home-based intervention for families of youth with social, emotional and behavioural problems. MST therapists engage family members in identifying and changing individual, family, and environmental factors thought to contribute to problem behaviour. Intervention may include efforts to improve communication, parenting skills, peer relations, school performance and social networks. MST is widely considered to be a well-established, evidence-based programme. We synthesise data from all eligible trials to test the claim that MST is effective across clinical problems and populations.

What are the main findings of this review?
Available evidence shows that MST reduces rates of out-of-home placement and arrest or conviction in the USA, but not in other countries. Moderate to low quality evidence shows that MST has positive effects on self-reported delinquency and parent and family functioning, but we find no evidence of overall impacts on youth symptoms, substance abuse, peer relations, or school outcomes. Predication intervals indicate that future studies are likely to find positive or negative effects of MST on all outcomes.

What are the implications for research and policy?
Our results stand in stark contrast to many previous reports and reviews on MST. Although most MST trials produce a mixture of positive, negative, and null findings, many reports focus selectively on positive, statistically significant results instead of all results. Careful appraisal of study methods and risks of bias is lacking in many published reports and reviews. Some investigators and many reviewers fail to consider alternative plausible explanations for results that appear to favour MST (e.g., lack of comparability of groups at baseline; differential attrition; confounding influences of race, gender, and additional attention paid to MST cases; and selective reporting of results).