Study links brain defects to pedophilia

Tuesday, December 18, 2007
Study links brain defects to pedophilia

Missing Tissue; Psychiatrist says he was taken aback by results

Tom Blackwell, National Post Published: Tuesday, December 18, 2007

A Canadian study involving MRI brain scans has uncovered intriguing new evidence that pedophiles are compelled to commit their reviled crimes because of neurological flaws.

The brains of such offenders seem to contain considerably less white matter than those of non-sexual criminals, the research concluded. That missing tissue could indicate a breakdown in the neurological network that processes erotic signals -- leading to an abnormal attraction to children, the authors theorize.

Dr. James Cantor, the psychologist who led the study, said he was taken aback by the variations between the pedophiles and non-sexual offenders.

"It's actually quite a dramatic difference," he said. "I expected ... to find some tiny little area of the brain that might be different between one group and the other. Instead I found these large swaths of material that was very low in volume [in pedophiles]."

Those brain deficiencies might be caused by something that harmed the fetus while their mothers were pregnant. If so, identifying that influence could help prevent the creation of potential new pedophiles, said the paper just published in the Journal of Psychiatric Research.

Outside experts raised some questions about the validity of the results, but said the findings, if borne out with more research, would be a major step forward in understanding sexual impulses generally.

"If it turns out to be found in everyone who has this problem, it would [point to] the mechanism for not only normal sexual interest but abnormal sexual interest too," said Paul Federoff, a psychologist at the Royal Ottawa Hospital who works with pedophiles. "That would be a huge development."

However, he said the research shows only a correlation between the brain deficiency and pedophilia, not necessarily a cause-and-effect relationship.

Scientists have traditionally believed that having a sexual preference for children was the result of environmental factors, such as sexual abuse or other trauma in childhood.

The focus of Dr. Cantor's research, though, has been exploring possible biological causes. Other studies he conducted, for instance, have found that pedophiles are more likely to be left-handed and have low IQs, both potential indicators of a neurological deficit.

For the latest research, he had MRI brain scans performed on 65 people he identified as pedophiles, and a control group of 62 criminals with no history of sexual offences.

Digital analysis of the MRI images indicated that the pedophiles tended to have smaller volumes of white matter over a relatively large area of the brain.

In simple terms, white matter is like the computer cable that links segments of grey matter, the brain's computers. The areas of white matter where pedophiles had deficiences happen to connect cortical regions that, other research suggests, process and respond to sexual clues. It is possible pedophiles have a disconnection, or insufficient connection, in that sexual-response network, the paper says.

That may either lead to pedophilia directly, or make people more susceptible to the problem if they are victims of outside influences, like child abuse, the study suggests.

Dr. Patrick Baillie, a Calgary psychologist who works with pedophiles, said the research is far from definitive, partly because some of those Dr. Cantor considered pedophiles may not truly meet the definition.

However, he said the notion of a neurological explanation for pedophilia makes sense to him. It might be the brain differences are caused by outside trauma at a young age, and the sexual preferences of that age are "locked in" for life, Dr. Baillie said.

Dr. Cantor said his arguments in favour of a biological explanation for pedophiles seem to resonate both with victims and parents of the offenders, based on letters he has received. Mothers of pedophiles have told him they were relieved to think that it was not necessarily something they did to their sons that turned them into sexual offenders.

tblackwell@nationalpost.com