Sexual Abuse: A Journal of Research and Treatment, Vol. 17, No. 2, April 2005 (
Testosterone, Sexual Offense Recidivism,
and Treatment Effect Among Adult Male
Lea H. Studer,
A. Scott Aylwin,
and John R. Reddon
The relationship between serum testosterone and sexual violence was examined
in a sample of 501 convicted adult male sex offenders attending an intensive
in-hospital group psychotherapy treatment program. It was found that men with
higher testosterone tended to have committed the most invasive sexual crimes
(p <.001, two-tailed). Further, a positive partial correlation (controlling for age)
between testosterone and sexual offense recidivism over a lengthy follow-up period
(mean = 8.9 years) was found. When the sample was separated into one group
that completed treatment and one group that did not, an important ameliorating
treatment effect was observed. Although controlling for age, serum testosterone
remained signiﬁcantly predictive of sexual recidivism for the treatment noncom-
pleter group (p <.05, two-tailed). For those who completed treatment testosterone
was no longer predictive of sexual reoffense (p >.05, two-tailed). Among con-
victed sex offenders, higher serum testosterone appears to be associated with
greater likelihood of further sexual violence. Effective therapy, however, appears
able to intercede in the inﬂuence of testosterone on sexually deviant behavior.
It is suggested that serum testosterone may be an informative static risk factor
and completion of intensive treatment should be accorded signiﬁcance in future
actuarially based risk prediction instruments.
KEY WORDS: testosterone; sex offenders; recidivism; treatment effect.
Androgens are steroid hormones that mediate sexual development and sexu-
ality. The most relevant hormone in this regard is testosterone, along with its active
metabolite dihydrotestosterone (DHT). Testosterone production is initiated when
gonadotropin-releasing hormone (GnRH) is secreted from the hypothalamus. In
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