MST Adaptations

Researchers have also developed a number of adaptations of MST to meet the needs of different populations of children, young people and their families. Some of these adaptations are now being used here in the UK.
MST Problem Sexual Behaviour (PSB)
Multisystemic Therapy for young people with problem sexual behaviour targets young people aged 10 to 18 years who have committed a sexual offence or a sexual assault on a family member which has come to the attention of children's social care. 
MST-PSB is built on the foundation of standard MST, is evidence-based and addresses the many factors that influence problem sexual behaviour.    
MST-PSB therapists only work with a few families at a time and see the young person and family in their home setting. During the treatment, they
  • address the denial by the family and young person that there is a problem
  • focus on the aspects of the young person’s environment that contribute to the sexual delinquency
  • help the parents or carers to build support networks
  • show the parent or carers how to provide unambiguous guidance and support so that the young person can develop social skills that will allow him or her to establish healthy relationships with friends. 
For more information about MST-PSB, please visit: or read the Community care Article, ‘Improving our response to children who display sexually harmful behaviour’ where Rory Patterson and Jessie Greisbach explain the steps Southwark Council has taken to boost support for children and social workers.
MST-Family Integrated Transitions (MST-FIT)
The MST Family Integrated Transitions (FIT) model uses standard MST principles with additional components to address the specific issues and contexts of young people returning home. In the US where it has been developed it provides individual and family services to young offenders with mental health and substance misuse during the period of transition from residential settings back to the community. The goals of the FIT programme include strengthening family relationships, reducing the young person’s substance misuse, improving his or her mental health and increasing pro-social behaviour and lowering the risk of offending where this is part of the presenting problem. Also, connecting the family with appropriate community supports and supporting the young person in reintegrating into school and to develop positive peer relationships.
The MST FIT programme combines a number of evidence-based interventions with the goal of targeting multiple determinants of antisocial behaviour, substance abuse and mental health issues in young people. The overarching framework of the intervention is derived from Multisystemic Therapy (MST) and this is combined with Dialectical Behaviour Therapy to target young people’s individual mental health needs and support those caring for them more effectively.
The model works for 3 to 4 months with young people and their carers while they are placed away from home, thus improving skill level of the current residential or foster carers and  also with the young person’s family to identify the issues which may present difficulties in order to plan a successful  return home. Once the young person has returned home, work continues with the family for a further four months and with other key agencies, such as social care and schools and also to support the family members to develop community based supports and reduce their longer term reliance on statutory services.
MST FIT has been implemented in four counties in Washington State, as well as in New York, Connecticut, and Illinois, and has provided a service to young people who are among the most difficult to treat in the youth justice, substance misuse and mental health treatment systems. There are currently MST FIT teams in Leeds and Northamptonshire, with a team in development in Reading.
The study aimed to:
  • identify the issues in implementing MST-FIT;
  • determine whether it is a feasible intervention;
  • identify other groups for whom it may be suitable.


For more information about the MST-FIT model please visit the University of Washington Department of Psychiatry and Behavioural Sciences website or view a short film about MST-FIT.

If you are interested in setting up an MST team, please visit the Implementation Process webpage.