Effectiveness of Multisystemic Therapy for Adolescents From Families With Intellectual Disabilities

Background of the study:

Over the years, a large body of research has shown that adolescents with intellectual disability are 3-4 times more likely to develop severe behaviour problems than adolescents without intellectual disability. Families in which adolescents and/or one or both parent(s) have an intellectual disability (from now on, families with ID) often deal with complex problems, putting the adolescent at an increased risk of out-of-home placement. Multisystemic therapy (MST) is an intensive home-based treatment, effective in reducing severe behaviour problems and preventing the out-of-home placement of adolescents. A specialisation of MST has been developed for families with ID: MST-ID. In MST-ID, among other alterations, simplified language and visual support is used, sessions are more structured and more time is scheduled for practicing exercises, and extra attention is paid to the generalisation of what has been learned in the sessions (with the aim of attaining long-term outcomes). Pilot studies show that when compared to standard MST, MST-ID shows similar or better treatment outcomes in families with adolescents with ID. Meanwhile, MST-ID has been disseminated more widely and the target population extended by including families in which only the parent(s) have an ID.

Objective of the study:

The aim of this study is to investigate the effectiveness of MST-ID for adolescents with severe behavioural problems from families with an intellectual disability (ID), compared to standard MST. It is hypothesised that MST-ID is more effective - in terms of fewer behavioural problems, more adolescents living at home, being in school/work, no new police contacts, less parenting stress - than standard MST. Treatment outcomes are considered both quantitatively and qualitatively.

Study design:

Quantitatively, the Propensity Score (PS) method is used to balance treatment groups and, combined with Multilevel Modelling (MLM), to estimate treatment effect over time. Qualitatively, the experiences of approximately 10 adolescents and/or parents are centralised. The qualitative research methods will be decided upon in a participatory manner with respondents (examples of potential research methods are interviews, focus group discussions, or photo elicitation).

Study population:

Adolescents (10-19y) with severe behavioural problems or delinquent behaviours, and their parent(s) receiving MST(-ID) treatment. All research participants must be from families where either the adolescent and/or parent(s) has/have ID.

Intervention:

Following standard referral procedures, families were either referred to standard MST or MST-ID treatment (i.e., non-randomly). Both standard MST and MST-ID are intensive, home-based treatments with 3-5 home visits per week, targeting the severe behavioural problems of adolescents across multiple life domains. MST-ID is tailored to the needs and skill deficits of adolescents and/or parents with ID. Concretely, more attention is paid to how therapists create engagement, implement interventions, and realise support from informal supports, in a tailored, developmentally appropriate, and simplified manner (meaning in a more structured way and using accessible language, among others), when compared to standard MST.

Research questions:

Building on the objectives, the following research questions were formulated:

Primary research questions:

• Is MST-ID superior, when compared to standard MST, in reducing rule-breaking behaviour of adolescents, according to parents?
• Is MST-ID superior, when compared to standard MST, in reducing rule-breaking behaviour of adolescents, according to adolescents?

Secondary research questions:

• Is MST-ID superior, when compared to standard MST, in reducing externalising and internalising behavioural problems of adolescents, according to parents?
• Is MST-ID superior, when compared to standard MST, in reducing externalising and internalising behavioural problems of adolescents, according to adolescents?
• Is MST-ID superior, when compared to standard MST, in reducing parenting stress?
• Is MST-ID superior, when compared to standard MST, in preventing short and long term out-of-home placement, delinquency, truancy or joblessness, and addictions of adolescents?
• Is MST-ID superior, when compared to standard MST, in realising improvements on family's social networks?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome parenting skills?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome family relations?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome social support?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome adolescent success in an educational or vocational setting?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome adolescent involvement with pro-social peers?
• Is MST-ID superior, when compared to standard MST, in improving the instrumental outcome change in adolescent problem behaviour?
• What are the experiences of adolescents and/or parents receiving MST-ID treatment?
• Do effects across subgroups of adolescents and/or parents with ID differ?

MST-ID is expected to be superior in achieving the aforementioned outcomes (#1-13) when compared to standard MST. Research questions #14-15 will be assessed exploratively, therefore no hypotheses have been formulated.

Referral Criteria:

• Known or suspected ID of the referred adolescent and/or their parent(s);
• Educational level of the referred adolescent and/or highest attained diploma of their parent(s) is indicative of potential ID.

Inclusion criteria

Study Sample:

• Adolescent must be 10 to 19 years old at the start of treatment;
• Adolescent presents with severe behavioural problems in at least two life areas;
• Adolescent lives with a family or there is a family the adolescent can live with, in which parent(s) have parental custody for a longer period of time;
• Parent(s) consent(s) and is/are willing to engage in treatment to prevent an out-of-home placement of the adolescent;
• Adolescent and/or parent(s) have a known or suspected intellectual disability (operationalised as an intelligence quotient [IQ] score of between 50-85 and additional deficits in adaptive functioning)
• Adolescent and/or parent(s) have sufficient knowledge of the Dutch language (as assessed by a clinician and/or researcher) in order to understand and answer the various (self-report) questionnaires.

Exclusion criteria

Study Participation:

• Adolescent lives independently;
• Adolescent presents with severe problematic sexual behaviours, without presenting with other severe behavioural problems;
• Adolescent presents suicidal, psychotic, or homicidal requiring specialised treatment (such as a crisis placement in a residential facility);
• Adolescent has a severe Autism Spectrum Disorder (level 2-3 according to the Diagnostic and Statistical Manual of Mental Disorders [DSM-V] criteria) or a severe ID (IQ score <50);
• Adolescent has internalising psychiatric problems which are the primary reason for referral, or has serious psychiatric problems (similar to #3 as well as for example eating disorder.