Chemical castration trials aim to prevent sex abuse

Paedophiles not convicted of a crime are being recruited for a research project aiming to show that men at risk of sexually abusing children can be identified and treated before they target a victim.

A clinical trial looking at the effectiveness of a ‘chemical castration’ therapy that cuts levels of the male hormone testosterone is already under way in Sweden.

However, scientists are taking the controversial further step of looking at whether men in the general population who are worried about their sexual urges can successfully be treated to prevent them committing crimes. They also hope to pinpoint ‘biomarkers’ — tell-tale substances in the blood or brain wiring patterns — that mark out individuals who could pose a danger to children.

The researchers stress that if such biomarkers are found, there is no question of them being used to conduct population screening for paedophiles. However, they could help psychiatrists or prison governors decide if certain individuals can safely be allowed near children, or who might benefit from a drug treatment.

Christoffer Rahm, from the Karolinska Institute in Stockholm, who heads the Priotab project, said: “One in 10 boys and one in 20 girls is sexually abused during childhood. This issue is hard to deal with but we must, because it affects all of us.

“Child sexual abuse causes a lot of suffering for the victims and their relatives ... it also has negative consequences for the perpetrator, who risks becoming totally isolated, depressed and sentenced to imprisonment.

“Up until now most of the attention has been on how to deal with perpetrators while they’re protected by the police or by the authorities, but by this stage children have already been harmed.

“With this research project, I want to shift focus and explore methods of preventing child sexual abuse from happening in the first place.”

Dr Rahm said a “handful” of men with paedophilic tendencies — none of whom had been convicted of any offence — had already been recruited by his team through a Swedish help line for people who fear their sexual appetites are out of control.

They were taking part in a study testing the effectiveness of degarelix, a prostate cancer drug that blocks signals from the brain that switch on production of testosterone, known to fuel the disease.

The aim is to compare 30 men receiving the drug with 30 others given a placebo treatment.

The scientists want to see if the drug can help the volunteers keep their sexual urges in check without causing unacceptable side effects.

Three days after receiving an injection of degarelix, 97% of treated men have almost no detectable levels of testosterone in their blood. Unlike some other hormone treatments, the drug does not cause an initial ‘flare’ that actually boosts levels of testosterone.

“The hypothesis we are testing is that this medicine has a clinically significant risk-reducing effect,” said Dr Rahm.

The biomarker study, which was still at a “very early phase”, would find out whether men who sexually abused children have any measurable traits that distinguish them from the general population. These could include molecules in the blood, or specific patterns of brain structure or activity.

Part of the research will involve showing participants pictures of adults and children in swim suits while they undergo functional magnetic resonance imaging brain scans.