An Exploratory Study of Multisystemic Therapy for Western Australian Adolescents with Antisocial Behaviours: Lessons Learned and Challenges Faced

ABSTRACT: Multisystemic Therapy (MST) is an intensive community-based, family intervention for older children and adolescents exhibiting juvenile antisocial behaviours. The MST intervention was implemented within the Western Australia Department of Health in 2005 and has since operated two clinical teams within the Perth metropolitan area. Adolescents exhibiting antisocial behaviours often meet diagnostic criteria of conduct disorder, a common mental and behavioural problem in children and adolescents, and ranked in the top five of leading causes of disease burden within Australian children. Conduct disorder negatively affects well-being of both the adolescent and family members, who experience repercussions of the adolescent’s behaviours e.g., verbal and physical assault in their home, police involvement, legal sanctions, and social exclusion. In the absence of effective intervention, conduct disorder predicts various adult mental illnesses, substance abuse, chronic unemployment, family and domestic violence, and incarceration. This exploratory study provides an overview of treatment outcomes extracted from longitudinal data collected from 749 research participants engaged in the WA CAMHS MST program between January 2005 and December 2024, including baseline, post-treatment, and limited 6-month follow-up data. The treatment outcomes were categorised in 4 different cohorts by year of engagement in the program as follows: 2005–2009, 2010–2014, 2015–2019, and 2020–2024. In addition to examining treatment outcomes, we explored demographic and clinical variations across cohorts to account for societal changes over the last 20 years. Influences such as rapid technological advancements and the COVID-19 pandemic have reshaped family mental health and well-being as well as service delivery models. Our findings highlight the importance of adaptable and sustainable therapeutic interventions to ensure their relevance, effectiveness, and long-term impact, particularly in ever-changing environments.