The sudden and uncontrollable paedophilia exhibited by a 40-year-old man was caused by an egg-sized brain tumour, his doctors have told a scientific conference. And once the tumour had been removed, his sex-obsession disappeared.

The cancer was located in the right lobe of the orbifrontal cortex, which is known to be tied to judgment, impulse control and social behaviour. But neurologists Russell Swerdlow and Jeffrey Burns, of the University of Virginia at Charlottesville, believe it is the first reported case linking damage to the region with paedophilia.

“We’re dealing with the neurology of morality here,” says Swerdlow. Since the area does not affect physical health, “it’s one of those areas where you could have a lot of damage and a doctor would never suspect something’s wrong,” he says.

“He wasn’t faking,” says Burns. “But if someone argues that every paedophile needs a MRI, the difference in this case was that the patient had a normal history before he acquired the problem. Most paedophiles develop problems early on in life.”


Massage parlours

The man, a schoolteacher, began secretly visiting child pornography web sites and soliciting prostitutes at massage parlours, activities he had not engaged in previously. Swerdlow says while the man felt that his new behaviour was unacceptable, “in his words, the ‘pleasure principle’ overrode his restraint”.

When the man’s wife found out he had made subtle sexual advances towards young children, he was legally evicted from his house, found guilty of child molestation and medicated for paedophilia.

The judge ruled that he had to pass a 12-step Sexaholics Anonymous rehabilitation program or face jail time. But the man was expelled after he failed to restrain himself from asking women at the program for sex.

The evening before his prison sentencing he took himself to a hospital complaining of headache and saying he was afraid he would rape his landlady.

Balance problems

After he was remanded to psychiatric care, he complained of balance problems and a MRI scan revealed an egg-sized brain tumour. Further tests found the man was also unable to write or copy drawings and was unconcerned when he urinated on himself.

But seven months after the tumour was removed, and after successfully completing the Sexaholics Anonymous program, the man returned home. In October 2001 he complained of headaches and secretly collected pornography once more. But after a MRI scan revealed tumour regrowth and it was removed, the behaviour again disappeared.

Swerdlow suggests that physicians who see personality changes coupled with an inability to write or copy pictures may now want to consider brain disease as a possible cause.

Behavioural neurologist David Rosenfield, of the Baylor College of Medicine in Houston, says: “They have an interesting patient. I would wonder whether the tumour caused hormonal changes.” Rosenfield thinks further research should investigate whether other problems with the orbifrontal cortex can be linked to paedophilia.

Burns and Swerdlow presented their findings in New York at the annual meeting of the American Neurological Association.