BackgroundAn adaptation of multisystemic therapy (MST) was piloted to find out whether it would yield better outcomes than standard MST in families where the adolescent not only shows antisocial or delinquent behaviour, but also has an intellectual disability.MethodTo establish the comparative effectiveness of MST‐ID (n = 55) versus standard MST (n = 73), treatment outcomes were compared at the end of treatment and at 6‐month follow‐up. Pre‐treatment differences were controlled for using the propensity score method.ResultsMultisystemic therapy‐ID resulted in reduced police contact and reduced rule breaking behaviour that lasted up to 6 months post‐treatment. Compared to standard MST, MST‐ID more frequently resulted in improvements in parenting skills, family relations, social support, involvement with pro‐social peers and sustained positive behavioural changes. At follow‐up, more adolescents who had received MST‐ID were still living at home.ConclusionsThese results support further development of and research into the MST‐ID adaptation.

Research on follow‐up outcomes of systemic interventions for family members with an intellectual disability is scarce. In this study, short‐term and long‐term follow‐up outcomes of multisystemic therapy for adolescents with antisocial or delinquent behaviour and an intellectual disability (MST‐ID) are reported. In addition, the role of parental intellectual disability was examined. Outcomes of 55 families who had received MST‐ID were assessed at the end of treatment and at 6‐month, 12‐month and 18‐month follow‐up. Parental intellectual disability was used as a predictor of treatment outcomes. Missing data were handled using multiple imputation. Rule‐breaking behaviour of adolescents declined during treatment and stabilized until 18 months post‐treatment. The presence or absence of parental intellectual disability did not predict treatment outcomes. This study was the first to report long‐term outcomes of MST‐ID. The intervention achieved similar results in families with and without parents with an intellectual disability.

ThuisBest is a newly developed family focused treatment that combines secure residential youth care with multisystemic therapy (MST), allowing adolescents to return home after secure residential youth care more quickly. The purpose of this pilot study was to examine treatment outcomes for adolescents in ThuisBest ( n = 86, Mage = 15.2 years, 63% boys) and to what degree those treatment outcomes could be predicted by client characteristics. The results showed that externalizing behavior problems and parenting stress had decreased at the end of treatment. After ThuisBest, 83% of the adolescents did not have new police contact, 72% lived at home, and 89% attended school or work. Almost none of the treatment outcomes could be predicted by any of the client characteristics. ThuisBest seems a promising trajectory, as it reduces the length of the stay in secure residential youth care, and may, therefore, be more cost-effective than standard secure residential youth care. However, given the lack of a control-group and follow-up data, findings must be interpreted as preliminary.