Effects of chemical castration on sex offenders in relation to the kinetics of serum testosterone recovery: Implications for dosing schedule

Introduction: A growing number of countries are adopting chemical castration as treatment and penalty for sex offenders. Aim: The aim of this study is to evaluate the outcome of chemical castration of sexual offenders with a focus on the kinetics of serum testosterone (T) recovery. Methods: This prospective analysis included 56 sex offenders imprisoned for sexual offenses at the National Forensic Hospital. Thirty-eight and 18 patients who received 3 and 6 months of leuprolide acetate injections were assigned to group A and group B, respectively. Main Outcome Measures: To evaluate treatment efficacy according treatment duration, psychobehavioral assessments and serum T levels were serially measured during the on-cycle and the following observational 12-month off-cycle. Results: Chemical castration and the associated decrease in serum T levels reduced the frequency and intensity of sexual thoughts in 76% and 71% of group A patients and in 78% and 72% of group B patients, respectively. Reductions in masturbation frequency were observed in 74% of group A and 83% of group B patients. The median Wilson's Sex Fantasy Questionnaire (SFQ) scores were also significantly reduced in both groups. In group A, an upsurge of serum T to the flare level was observed during the first 2 months of the off-cycle, accompanied by an intense sexual drive and fantasy. In group B, serum T gradually recovered to the baseline level and continued to upsurge beyond baseline levels during the observational period. SFQ scores of group A returned to pretreatment levels following the observational period; however, SFQ scores of group B remained suppressed. Lack of objective assessments for psychobehavioral outcomes was a limitation. Conclusions: The efficacy of chemical castration varied according to the treatment duration. Regarding the kinetics of serum T recovery, maintaining at least 6 months of treatment warranted stable control of an excessive sexual drive following treatment cessation.