Psychosocial treatment programmes to reduce reoffending among people with sexual offence histories.
This summary is part of the Crime Reduction Toolkit, which presents the best available research evidence on what works to reduce crime.
Focus of the intervention
Psychosocial programmes deliver therapeutic treatment to offenders that do not rely on deterrence or punishment. Psychosocial treatments include:
- behavioural therapy
- cognitive behavioural therapy (CBT)
- insight-oriented therapy
- multisystemic therapy (MST)
- therapeutic communities
Although psychosocial treatments cover a range of approaches, they share common features. For example, CBT that aims to enhance social skills, reduce deviant sexual attitudes and improve self-control can overlap with relapse prevention programmes that help offenders cope with risk. Similarly, therapeutic communities and MST involve group-based approaches, but incorporate some elements of CBT.
This summary is based on two meta-analytic reviews.
Review one drew upon 35 studies (published up to 2021), which examined the effectiveness of psychosocial treatment programmes in reducing sexual reoffending. The primary studies in Review one covered CBT (20 studies), behavioural therapy (five studies), therapeutic communities (five studies), MST (three studies) and insight-oriented therapy (two studies).
Review two drew upon 27 studies (published up to 2010), which examined the effectiveness of psychosocial treatment programmes in reducing sexual, violent and non-sexual reoffending among male sex offenders. The primary studies in Review two covered CBT (21 studies), therapeutic communities (four studies), MST (two studies) and insight-oriented therapy (two studies).
Review one is an update of Review two. As such, the Effect and Moderator sections below are based on Review one. Review two provides additional information for the Mechanism and Moderator sections only.
The 35 studies in Review one produced 37 tests of the intervention. Of these, 13 were carried out in Canada, 11 in USA, and the remaining 13 in ‘other’ locations (Australia, Germany, the Netherlands, New Zealand or the United Kingdom). The 27 studies covered by Review two produced 29 tests of the intervention – 11 in Canada, eight in the USA, three from the United Kingdom, three from Germany and four from ‘other’ locations.
See also Psychological treatment of adults convicted of sex offences against children.
Effect – how effective is it?
Pooling the results of all the studies included in the two reviews, the evidence suggests that psychosocial treatment programmes have reduced reoffending in people with sexual offence histories. There is also some evidence that they have sometimes increased reoffending.
Review one found that, overall, the treatment programmes reduced sexual reoffending by 31.8%. Reoffending – measured in terms of subsequent arrest, charge or conviction – declined from 13.6% to 9.3%, a reduction of 4.3 percentage points. Review one also found treatment programmes resulted in statistically significant reductions in general and violent reoffending.
How strong is the evidence?
Review one and Review two were sufficiently systematic that most forms of bias that could influence the study conclusions can be ruled out.
The reviews demonstrated a high-quality design in terms of transparent and well-designed search strategies, consideration of bias and attention to the validity of outcome constructs.
Potential sources of bias existed in the primary studies covered by the reviews. For Review one, these included:
- potential conflict of interest due to author affiliation with the treatment programme in 24 of the 35 primary studies
- only seven studies were randomised controlled trials (RCTs)
For Review two, sources of bias included:
- potential conflict of interest due to author affiliation with the treatment programme in 15 of the 27 primary studies
- considerable variability in the findings of the primary studies
- only six of the studies were RCTs, five of which had sexual offending as an outcome
- one third of the studies had small sample sizes (up to 50 offenders)
Mechanism – how does it work?
Review two suggested psychosocial treatment programmes are assumed to reduce reoffending by helping offenders to:
reduce deviant sexual attitudes
improve self-control
develop social skills
take different perspectives
cope with stressors
However, Review two did not empirically test these assumptions as the primary studies did not provide the necessary information to do so.
Moderators – in which contexts does it work best?
There is evidence that psychosocial treatment programmes vary in effectiveness according to specific features of the programme and the context in which they are implemented.
Both reviews identified a number of factors that moderated the overall impact of the programme. Review 1 moderators included:
- Programme focus: Non-specialised treatment programmes were found to be ineffective or ‘do more harm than good’, unlike specialised treatment programmes that focused on the factors that contribute to a person’s offending.
- Offending risk: Treatment programmes for high- and medium-risk offenders were more effective than those for low-risk offenders. Risk was measured using a risk scales specific to the primary study or the rapid risk assessment for sexual offence recidivism (RRASOR).
- Prior offending: Treatment programmes were more effective when participating offenders had higher rates of prior offending.
- Programme setting: Treatment programmes in outpatient or prison settings were more effective than treatment programmes in other settings.
Review two identified a number of programme features associated with effectiveness for reducing sexual and general reoffending. More effective programmes were:
- Cognitive-behavioural and MST programmes rather than programmes using other treatment approaches. MST was found to have particularly large effects on reoffending in two RCTs.
- Programmes providing individual treatment or a mixture of group and individual support rather than group-only treatment.
- Treatment programmes specifically tailored to sexual offending.
- Programmes focused on higher risk offenders, assessed by prior convictions and victim characteristics.
- Programmes delivered in hospital or outpatient settings.
While Review one and Review two suggested risk level and treatment specialisation were important predictors of sexual reoffending, Review one found their effects to be stronger than Review two.
Implementation – what can be said about implementing this initiative?
Neither review gave an account of how the intervention was implemented, or any implementation challenges encountered by the primary studies.
However, Review two theorised that better-implemented studies had a greater impact. For example, studies which focused on only one programme and were implemented in only one location tended to reveal better results than studies evaluating different programmes across different institutions.
Economic considerations – how much might it cost?
Neither review mentioned the costs or benefits of psychosocial treatment programmes and no formal economic analysis was provided.
General considerations
- Most of the evidence from the reviews was taken from studies in North America, so caution should be taken when applying the findings of the reviews to other geographical contexts, including the UK.
- Review one did not specify the sex of the offenders in the primary studies.
- Review one did not specify who the comparison group was in its meta-analysis.
- All data in Review one was collected by only one author.
- With Review two, the duration of treatment varied substantially within the primary studies, ranging from 8 to 281 weeks. Additionally, almost a third of studies in Review two did not provide duration data.
- Review two only covered studies up to 2010.
- The findings of these reviews suggest that the context of programme delivery and treatment setting may be important for understanding outcomes. For example, while Review two found that CBT approaches had good potential, features such as the risk level of the treated offenders were found to significantly affect treatment success.
Summary
- Overall, the evidence suggests that psychosocial treatment programmes have reduced sexual and general reoffending among sex offenders.
- While Review two found CBT and MST approaches to be particularly effective forms of psychosocial interventions for sex offenders, Review one highlighted two important factors to consider with psychosocial treatment programmes: the level of risk posed by the offender and how specialised the treatment is that is provided by the programme.
- Additional evidence is required to understand the mechanisms by which treatment programmes reduce crime, how their implementation affects the impact they have, and how much they cost.
Reviews
Review one
Reference
Holper L, Mokros A and Habermeyer E. 2024. ‘Moderators of sexual recidivism as indictors of treatment effectiveness in persons with sexual offence histories: An updated meta-analysis’. Sexual Abuse 26(3), pp 255–291.
Review two
Reference
Schmucker M and Lösel F. 2017. ‘Sexual offender treatment for reducing recidivism among convicted sex offenders: A systematic review and meta-analysis’. Campbell Systematic Reviews 13(1), pp 1–75.