Abstract: We included ten studies involving data from 944 adults, all male. Five trials involved primarily cognitive behavioural interventions (CBT) (n = 664). Of these, four compared CBT with no treatment or wait list control, and one compared CBT with standard care. Only one study collected data on the primary outcome. The largest study (n = 484) involved the most complex intervention versus no treatment. Long-term outcome data are reported for groups in which the mean years 'at risk' in the community are similar (8.3 years for treatment (n = 259) compared to 8.4 in the control group (n = 225)). There was no difference between these groups in terms of the risk of reoffending as measured by reconviction for sexual offences (risk ratio (RR) 1.10; 95% CI 0.78 to 1.56). Four trials (n = 70) compared one behavioural programme with an alternative behavioural programme or with wait list control. No meta-analysis was possible for this comparison. For two studies (both cross-over, n = 29) no disaggregated data were available. The remaining two behavioural studies compared imaginal desensitisation with either covert sensitisation or as part of adjunctive drug therapy (n = 20 and 21, respectively). In these two studies, results for the primary outcome (being 'charged with anomalous behaviour') were encouraging, with only one new charge for the treated groups over one year in the former study, and in the latter study, only one new charge (in the drug-only group) over two years. One study compared psychodynamic intervention with probation. Results for this study (n = 231) indicate a slight trend in favour of the control group (probation) over the intervention (group therapy) in terms of sexual offending as measured by rearrest (RR 1.87; 95% CI 0.78 to 4.47) at 10-year follow-up. Data for adverse events, 'sexually anomalous urges' and for secondary outcomes thought to be 'dynamic' risk factors for reoffending, including anger and cognitive distortions, were limited. The inescapable conclusion of this review is the need for further randomised controlled trials. While we recognise that randomisation is considered by some to be unethical or politically unacceptable (both of which are based on the faulty premise that the experimental treatment is superior to the control – this being the point of the trial to begin with), without such evidence, the area will fail to progress. Not only could this result in the continued use of ineffective (and potentially harmful) interventions, but it also means that society is lured into a false sense of security in the belief that once the individual has been treated, their risk of reoffending is reduced. Current available evidence does not support this belief. Future trials should concentrate on minimising risk of bias, maximising quality of reporting and including follow-up for a minimum of five years 'at risk' in the community.

Plain-language summary: We identified 10 relevant studies involving data from 944 adults, all male. Few of these studies provided information about the primary outcome of this review, which was reoffending. This was usually because studies did not collect data for a sufficiently long period outside prison or the treatment setting. Many studies relied on other outcome measures (for example, anger or social skills) chosen by investigators in the hope that they were linked in some way with future offending, although it cannot be stated with certainty that such connections reliably predict reoffending. Five of the trials we found involved 664 men and used primarily cognitive behavioural interventions (CBT). In the largest study, which had the most complex and intense 'package' of treatment both within and outside of prison, there was no difference between the group who had received CBT and those who had not in terms of the risk of reoffending as measured by reconviction for sexual offences. One study, involving 231 men, compared psychodynamic intervention with standard care, which was probation, and suggested that probation was mildly superior in terms of reducing reoffending. Behavioural programmes were looked at in four trials involving 70 men. For two studies, not enough data were reported to assess the effectiveness of treatment. For the remaining two, encouraging results with regards to reconvictions and self-reported urges have to be treated with caution as the studies are relatively old, meaning that many participants would not now seek or be offered treatment, as some of the targeted behaviours have been decriminalised. Data for adverse events, 'sexually anomalous urges' and for secondary outcomes thought to be 'dynamic' risk factors for reoffending, including anger and cognitive distortions, were limited. We concluded that further randomised controlled trials are urgently needed in this area, so that society is not lured into a false sense of security in the belief that once the individual has been treated, then their risk of reoffending is reduced. Currently, the evidence does not support this belief.