Testosterone levels not the key piece of the puzzle

A recent study by a group of researchers at the Royal Ottawa Health Centre has linked a certain hormone to recidivism in sex offenders, and it isn’t testosterone.

The study, published in the Journal of the American Academy of Psychiatry and Law Online, suggests the luteinizing hormone (LH) and the follicle-stimulating hormone (FSH) are better predictors of reoffending than the principle male hormone.

“We’ve known for some time that testosterone is associated with aggression and sexuality in primates and human beings,” said Dr. John Bradford, clinical director of the Forensic Treatment group at the Royal Ottawa Health Centre.

According to Dr. Bradford, there have been lots of studies regarding men who are frustrated and have lost their sexual drive.  As a result, they become more passive.  If they are then given replacement hormones, their testosterone levels rise and their sexual drive comes back.  There is little evidence that aggression may be heightened as well.

Bradford says anti-androgen medications have been known to critically affect testosterone as well as the LH.  Anti-androgen decreases deviant sexual fantasies, sexual urges and recidivism.   Again, there was also evidence that aggression as a personality trait is affected.

The research

The study, which Dr. Bradford began in 1980, involved 771 men aged 18-71, all of whom were convicted of a sexual offence.  Thirty-six per cent of the men were “intrafamilial offenders against children”, 24 per cent “extrafamiliar offenders against children”, 22 per cent exhibitionists, 9 per cent rapists, and 8 per cent offenders against “heterogeneous victim types.”  Two thirds of the offenders were referred to the clinic by a judge or lawyer, 18 per cent were referred by a doctor, and 5 per cent were self-referred.

Samples of  hormone levels were taken throughout their stay.  Canadian Information Police Centre (CIPC) kept track of the offenders after their release  to see who had reoffended:  18 and 28 per cent of men reoffended sexually and violently, after being followed for an average of 11 years afterward. These men had higher levels of LH and FSH.  The study indicates these particular hormones may play a larger role in the offenses.

“Most studies have shown that testosterone is particularly relevant with regard to sexual aggression and consequently, several different drugs have been used that target this hormone,” Dr. Drew Kingston, one of the researchers involved in the study.

“The results of this study suggest that other hormones may be important and therefore drugs that selectively target these hormones may be more beneficial in reducing the likelihood of future sexual offending.”

However he advises caution in making assumptions about the research:   “It should be stressed that these findings are novel and need replications,” stresses Dr. Kingston.  “It is also important to note that this study is correlational and does not suggest causation.”

Because testosterone has been linked in males to sexually motivated behaviour, Dr. Richard Krueger, associate clinical professor of psychiatry at Columbia University, says this is a surprising find.

“The fact that other hormones have been related is unexpected and suggests further research,” said Dr. Krueger.

But the direct connection between hormone levels and human behavior is a very complicated mechanism.   There has been very little work done regarding the relationship between hormones and recidivism.  Kingston and Bradford took a close look at hypersexuality, or individuals whose sexual drive is higher than average, and found that this increased the hazard ratio by 10 percent.

“The results of this study suggest that other hormones may be important and therefore drugs that selectively target these hormones may be more beneficial in reducing the likelihood of future sexual offending,” says Dr. Kingston.

Genetic patterns in pedophiles

LH, which is released from the brain as a pre-hormone for the release of androgen, is polypeptide, or a basic protein-like substance close to a gene.

Testosterone has been linked to aggression and sexuality in males and was thought to be the predictor of recidivism among sex offenders. New research suggests levels of luteinizing hormone (LH) can better be used to test  this behaviour.

Previous studies have found that the brains of pedophiles behave differently when they were stimulated to produce LH.  Similarly, a basic genetic study has linked a pattern of transmission in  pedophiles’ families,  there may be a genetic basis for this kind of sexual behaviour.

But again, Bradford stresses the genetic model was very complicated. “You cannot look at someone’s luteinizing hormone levels, unless they were enormously high, and say it increases risk,” says Dr. Bradford.

We can view this area of research as a step towards increased understanding of what we already know about the relationship between hormones and human behavior.

“It’s not so much that it’s a direct translation or research with regards to risk,” says Bradford, “but I think it’s more interesting in where it points in other directions and reinforces some of these other things we know about which require other research.”