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Treatment for people who commit sexual offences is aimed at lowering the risk that they will commit offences in the future. But research studies over decades show mixed results for long-term prevention of offences. Some aspects of treatment show positive results. But more research is needed to find which elements of treatment help people who have committed sexual offences avoid that behaviour in future.
Such research could help improve treatment programs as well as avoid reoffending and the costs to the criminal justice system that sexual offences cause. Research shows that more effective treatments:
- target risk factors that can be changed,
- are provided more often and for longer periods for people at higher risk, and
- follow the principles of Risk–Need–Responsivity (evidence-based treatment matched to the needs of the person treated).
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Does Treatment Work for Sexual Offences?
In her presentation for the International Forensic Psychiatry Lecture Series, Dr. Franca Cortoni explained that effective treatment must result in a change to the risk factors for sexual offences among patients. The change must be big enough to reduce the likelihood that they will sexually reoffend.
More than 100 studies have been conducted to find whether treatment changes these risk factors and results in fewer reoffences. Many of these studies show positive results.
But meta-analyses that examine studies together show that many studies had problems that could affect their results. Few studies randomly assigned participants to groups for a treatment versus no treatment or an alternative treatment, which is considered the strongest type of study.
And the results are mixed. For example, two studies found no effect of treatment on sexual reoffending after eight or 10 years. But when researchers analyzed results from one of these studies, participants who made gains during treatment were less likely to reoffend than those who did not.
Other research has cast doubt on whether improvements during treatment can predict future offences. Studies that asked participants about risk factors before and after treatment showed that change does not predict whether participants will reoffend. In fact, questionnaire scores before treatment better predicted offences than those after treatment. But it is unclear why. Treatment may teach participants socially desirable things to say rather than actually changing their thinking. Or questionnaires may fail to measure psychological change in people who commit sexual offences.
An exception is the Violence Risk Scale–Sexual Offense Version (VRS-SO). Participants’ improved scores on this questionnaire consistently predicted fewer violent and sexual reoffences.
Designing More Effective Treatment Programs
Some research evidence exists to help design treatment programs. Studies show that risk factors for sexual offending include difficulties with:
- cognition, especially thinking that supports sexual offending;
- psychological functioning and feelings, such as trusting those close to the person;
- relationships and functioning in society;
- regulation of emotions; and
- regulation of sexual thoughts and behaviours.
The most effective treatments are based on the principles of Risk–Need–Responsivity, both for all criminal and sexual offences.
First, the therapist should assess the person’s risk of sexually reoffending. This risk is based on both risk factors that cannot change (for example, what they have done in the past and their early life) and factors that can change. Questionnaires to assess risk in people who have committed sexual offences, such as the VRS-SO, are useful for this assessment. Then, people at higher risk should receive more intensive treatment (for more hours each week) for a longer duration (more weeks) based on their needs.
Treatment should target the person’s risk factors that can be changed. These include changing attitudes and feelings that support the person’s offending behaviour, promoting affection and communication with their family, associating with good role models, developing healthy emotional skills, and replacing unhealthy sexual behaviour patterns with healthier alternatives.
The therapist should choose types and styles of treatment that will work for their patient, such as:
- cognitive-behavioural therapy
- modelling
- skill building
- reinforcing pro-social behaviour
- practising new skills through role-playing
- providing concrete verbal suggestions, including explaining reasons and prompting the participants
Treatment should also consider the patient’s cognitive factors, personality, learning styles, abilities, and other psychological diagnoses. It should address the person’s beliefs about whether they can change.
A good relationship between the therapist and their patient is also important in lowering sexual reoffending. The participant’s trust in the therapist and engagement in therapy, as well as the therapist’s empathy and genuineness, can influence the effectiveness of treatment.
New Research Study
Dr. Cortoni is helping design a new treatment program aimed at improving risk and boosting protective factors for committing sexual offences to lower the risk of reoffending. Researchers will randomly assign participants to the new treatment or an existing treatment and follow participants over time to find their rate of reoffending.
For more details, watch the recording of the November 20, 2025, lecture, “Does Treatment Truly Reduce Sexual Offending? Current Knowledge and Future Directions” on our website.
Written by Carolyn Brown and approved by Dr. Franca Cortoni.
