Genetics of sex offenders
Sexual behaviour clinic gathers data on offenders for 33 years
Researchers at the Royal Ottawa Hospital are helping to sketch out a hormonal profile of those sex offenders who re- offend.
Researchers at the Royal Ottawa Hospital are helping to sketch out a hormonal profile of those sex offenders who re- offend.
A group of researchers at the Royal Ottawa Hospital recently published a study in the Journal of the American Academy of Psychiatry and the Law, which relates the levels of two hormones with criminal recidivism.
The study found levels of luteinizing hormone ( LH) and follicle- stimulating hormone ( FSH) were related to incidence of re- offending. While the study stops short of proving a causal effect — causes of sexual behaviour and aggression are complex, to say the least — it does provide a step forward in an area of science that is little understood yet which stands to offer clearly important benefits, in terms of community safety, over the long term.
The study has been decades in the making. Dr. John Bradford, clinical director of the Forensic Treatment Unit of the Royal Ottawa Health Care Group, started a sexual behaviour clinic there 33 years ago. By now, data has been recorded from almost 5,000 patients.
The study just published looks at 771 men, from age 18 to 78, who were assessed at the clinic between 1982 and 1996. All had been convicted of a sexual offence. Two- thirds were referred to the clinic by either a judge or a defence lawyer. Another 18 per cent were sent by their doctor, and five per cent were self- referred.
Among the subjects, 36 per cent were classified as “intrafamilial offenders against children,” 24 percent were “extra-familial offenders against children,” 22 per cent were exhibitionists, nine per cent were rapists of adult women and eight per cent were offenders against “heterogeneous victim types.”
During their time at the clinic, samples were collected to measure hormone levels.
A greater understanding of the hormonal causes of sexual offending and recidivism is very important to protect the public.
DR. JOHN BRADFORD
CLINICAL DIRECTOR
Using the Canadian Police Information Centre ( CPIC), the research team kept track of those men after they returned to live in the community, to see which, and how many of them had re- offended.
The followup period ranged from one to 20 years, with a mean of 11 years. Over that period, the percentage of those men who re- offended sexually and violently, were 18 and 28 per cent respectively ( for purposes of the study, criminal charges were enough to count as re- offending, whether followed by a conviction or not).
The study found that the hormone levels for LH and FSH were related to that recidivism and suggested that they were better predictors of it than testosterone, which was a surprising result.
One hope is that the findings could eventually point toward the discovery of genes that play a role in criminal sexual behaviour.
At the same time, Bradford cautions that the study is only one step in on a very long road toward understanding the relationship between the hormones and always- complicated human behaviour. The brain, he says, is incredibly hard to understand.
“There are 38 billion brain cells, for example, and they are all interconnected in many ways. It’s more than the greatest supercomputer you’d ever imagine.”
An independent commentary on the study, which was also published by the journal, praised the study as a “welcome relief for those of us who value solid research in a difficult area so often dominated by salespeople, moralizers and zealots.”
For Bradford, the study was a chance to let the information he started compiling so long ago provide data crucial for such studies. “A greater understanding of the hormonal causes of sexual offending and recidivism is very important to protect the public,” he said. “And particularly the vulnerable in the public, the women and children.”