This study aims to evaluate the effectiveness of the Multisystemic Therapy (MST) intervention for Australian families invloved with the Specialist Child and Adolescent Mental Health Service (CAMHS). This program was implemented within the Western Australian Department of Health in 2005, and has continually operated two small clinical teams within the Perth metropolitan area since then. This intervention was specifically chosen to improve service access, engagement, and intervention with vulnerable families having young persons with a history of significant and enduring behavioural problems. The study reports on data collected from July 2007 to July 2013 which includes baseline, post‐treatment, 6‐month, and 12‐month follow‐up. There were 153 MST families participating in the research at all time points (71% male; 11% Australian Aboriginal; average youth age was 13.6 years). Caregivers completed a set of questionnaires including Child Behaviour Checklist, Parenting Styles and Dimensions Questionnaire, and Depression, Anxiety and Stress Scale. One‐way repeated measure ANOVA were used to measure changes over time. Significant caregiver‐reported improvements in all measures were reported at post‐treatment, and most improvements were maintained at the follow‐up periods of 6 and 12 months post‐intervention. These preliminary outcomes demonstrate that the 4–5 month MST intervention significantly reduces behavioural problems and emotional difficulties in young Australians and these improvements are generally maintained by caregivers over time. Primary caregivers reported improved skills and mental health functioning that were also maintained over the follow‐up period. A proposed randomised controlled trial of the program will address potential placebo and selection bias effects.

Poor parental mental health is one of the risk factors for child emotional and behavioural problems because it reduces caregiver’s ability to provide appropriate care for their child. This study aimed to measure changes in parenting factors and adolescent behaviours after Multisystemic Therapy (MST), and to explore the mediating role of discipline approaches on the relationship between parental mental health and adolescent behavioural problems. This retrospective study extracted data collected from 193 families engaged with the MST research program during 2014–2019. Data was collected at different time points (pre-treatment, post-treatment, 6- and 12-months follow-up). Statistically significant changes were found in adolescent behaviours and parenting factors following the MST intervention and these positive changes were maintained over the following 12 months. Results of the parallel multiple mediator model analysis confirmed mediating effects of discipline approaches on the relationship between parental mental health and adolescent’s behavioural problems. The findings suggested that parental mental well-being significantly contributes to effectiveness of parenting, which resulted in positive changes in adolescent’s behavioural problems. It is recommended caregiver’s parental skills and any mental health issues are addressed during the intervention to enhance positive outcomes in adolescent behaviour.