Evaluating the effects of multisystemic therapy for adolescents with intellectual disabilities and antisocial or delinquent behaviour and their parents.

Families were not randomly assigned to treatment, so the groups differed before treatment and the comparison relied on statistical adjustment. 45% of the MST-ID families were excluded from the comparison because they differed too much from standard MST families, and the paper states that results apply to 55% of the research sample. MST-ID was delivered as a package with several added elements, so the contribution of any single component cannot be separated. Researchers were not blind to treatment condition, and data management was not fully independent. Follow-up was by telephone interview, and only 87 of 128 families gave consent for the interview. Treatment duration was not controlled, and MST-ID lasted a mean of 5.1 months versus standard MST at 4.4 months. The subgroup in which both adolescents and parents had intellectual disabilities could not be compared because the two treatment groups were too different to balance.

Do not conclude MST-ID is proven better than standard MST. The groups were not randomly assigned, the main outcomes did not differ at treatment end, and the comparison analysed only 63 families after exclusions.