Vol. 1, No. 4 , 1995, Page 4


Attempts to reduce aggression and sexual predation in male sex offenders have included surgical castration and chemical castration (the use of female hormones to suppress testosterone levels). Studies suggest that either approach can be effective; a 1989 German study by Wille and Beier, for instance, compared 99 surgically castrated sex offenders and 35 non-castrated sex offenders about a decade after their release from prison, and found that the recidivism rate of castrated offenders was 3%, while the rate for non-castrated offenders was 46%.

Castration is not an accepted practice in the United States, however, because of both ethical and medical concerns. But a new study suggests that even mild reductions in testosterone levels -- far short of the drastic reductions induced by castration -- can significantly reduce male aggression.

Peter Loosen and colleagues suppressed the gonadal function of eight normal men by administering a gonadotropin-releasing hormone antagonist, while keeping the subjects' testosterone levels in the low-normal range through the use of synthetic testosterone injections. The researchers say "this design allowed us to prospectively study behavioral changes in normal men during mild reductions (rather than during complete suppression) of serum testosterone levels."

The researchers report that all of their subjects showed marked reductions in outward- directed anger during the experiment, while half exhibited reductions in anxiety and sexual desire. This suggests, they say, that "measures of outward-directed anger are most sensitive to small reductions in circulating testosterone concentrations."

The researchers' experiment is of interest in light of studies by James Dabbs et al. (See Crime Times, Vol. 1, No. 3, Page 2 ) which strongly suggest a link between elevated testosterone levels and violence, delinquency, substance abuse, and prison rule violations.


"Effects on behavior of modulation of gonadal function in men with gonadotropin- releasing hormone antagonists," Peter T. Loosen, Scot E. Purdon, and Spyros N. Pavlou, American Journal of Psychiatry, 151: 2, Feb. 1994. Address: Peter T. Loosen, Health Research Chief, Psychiatry Service (116A), Veterans Affairs Medical Center, 1310 24th Ave. South, Nashville, TN 37212-2637.

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