Does specialised treatment for sexually abusive behaviour in adolescence reduce reoffending into adulthood? A quasi-experimental follow-up to age 25

Abstract Objectives Evidence pertaining to the effectiveness of specialized interventions for young people who commit harmful sexual behaviours is equivocal and sparse. The current study used a quasi-experimental design to evaluate the effectiveness of a specialized treatment program for harmful sexual behaviours in adolescence. Methods Participants included 284 young people referred for serious sexual offences who were screened and accepted for treatment, and a comparison group of 370 untreated adolescents also adjudicated for serious sexual offences. This study builds on a previous evaluation that followed participants to age 18 by extending the follow up to age 25, thereby providing evidence on the program’s effectiveness during the transition to adulthood. Cox survival models estimated the rate of subsequent any, sexual, violent, and non-violent offending, using covariate balancing propensity score weighting and stabilised inverse probability of treatment weighting. Results ​Treatment was associated with a significantly lower rate of any and sexual reoffending, but not violent and non-violent offending. Conclusions These findings suggest that the benefits of specialized treatment in adolescence extend into adulthood. The findings are discussed in terms of cost effectiveness of specialized treatment for harmful sexual behaviours and methodological implications for evaluating low-base rate phenomenon such as sexual recidivism​.