The impact of testosterone-lowering medication on recidivism in individuals convicted of sexual offenses

Figures & data

Table 1. Differences between individuals with (+TLM; n = 54) and without (−TLM; n = 79) TLM-treatment.

Variable	+TLM		−TLM		MDiff	Comparison
	M	SD	M	SD		F	df	η^2p
Previous convictions	5.1	3.9	4.6	4.6	+ 0.6	0.51	1, 131	.00^ns
Sexual convictions	1.4	1.5	0.9	1.0	+ 0.6	6.89	1, 131	.05*
Age at first conviction	23.0	9.4	25.0	10.2	− 1.9	1.24	1, 131	.01^ns
Age at index offence	33.9	9.4	32.8	8.9	+ 1.1	0.46	1, 131	.00^ns
Last imprisonment^a	13.9	8.2	8.3	6.4	+ 5.6	19.78	1, 131	.13***
Age at release	48.1	10.0	42.4	10.7	+ 5.8	9.85	1, 131	.07**
Static-99R	4.9	2.3	4.1	2.3	+ 0.8	4.12	1, 131	.03*
FTA treatment duration^a	5.1	2.4	2.5	1.6	+ 2.6	56.03	1, 131	.30***
Time at risk^a	6.3	3.7	6.6	3.9	−0.4	0.34	1, 131	.00^ns

Note: +TLM: psychotherapy + TLM-treatment group, −TLM: psychotherapy - TLM-treatment group, M: mean, SD: standard deviation, M_Diff: mean difference (M_Diff = M_+TLM – M − TLM), df: degrees of freedom, ^nsnot significant.

^a In years.

* p < .05; **p < .01; ***p < .001.

Table 2. Index offence, kind of former imprisonment, treatment status at the FTA and diagnoses according to ICD-10 of the treatment group with (+TLM; n = 54) and without TLM (−TLM; n = 79).

	+TLM		−TLM		χ²(2,133) or	Cramer-V or φ
	n	%	n	%	χ²(1,133)
Sexually motivated homicide	5	9.3	6^a	7.7	6.234	.22*
Rape / sexual assault against adults	16	29.6	40	51.3
Sexual abuse of children	33	61.1	32	41.0
Released from prison	19	35.2	66	83.5	32.521	.49***
Released from forensic psychiatry	35	64.8	13	16.5
Still in treatment at the FTA	30	58.8	21	26.2	11.389	−.29***
Paraphilic disorder^b	50	92.6	36	45.6	31.038	−.48***
Paedophilic disorder	32	59.3	26	32.9	9.055	.26**
Sadistic disorder	5	9.3	3	3.8	Fisher’s exact test^c	.11^ns
Personality disorder	26	48.1	47	59.5	1.667	.11^ns
Intellectual disorder	7	13.0	3	3.8	Fisher’s exact test^c	−.16^ns

^aIn the − TLM, one person had been convicted of exhibitionist acts and is not listed here.

^b Since some individuals had several diagnoses, the numbers do not add up to 100%.

^c 50% of cells had an expected frequency less than 5.

* p < .05; ** p< .01; ***p < .001.

Table 3. Recidivism rates of the treatment group with TLM (+TLM; n = 54) and without TLM (−TLM; n = 79).

	+TLM		−TLM
	n	%	n	%	χ²(1,133)	φ
General recidivism	15	27.8	41	51.9	7.656	−.24**
Serious recidivism	3	5.6	8	10.1	Fisher’s exact test	−.08^ns
Violent recidivism	1	1.9	12	15.2	6.470	−.22*
Sexual recidivism	3	5.6	8	10.1	Fisher’s exact test	−.08^ns

Note: +TLM: psychotherapy + TLM-treatment group, −TLM: psychotherapy - TLM-treatment group.

* p < .05; **p < .01; ***p < .001.

Figure 1. Kaplan-Meier curves of the + TLM (n = 54) and the − TLM (n = 79) regarding different forms of recidivism.

Table 4. Cox-regression on the prediction of general recidivism with TLM- treatment as time-dependent covariate, controlled for Initial risk at the time of release measured by static-99R for the + TLM (n = 54) and the − TLM (n = 79).

Variable	B	SE	Hazard ratio (Exp(B))	95% confidence interval of Exp(B)		p
				Lower	Upper
TLM-treatment^a	−.778	.312	.459	.249	.846	.013
Static-99R	.172	.057	1.188	1.062	1.328	.003

Modell χ²_(2,133)=14.865, p = .001; -2Log-Likelihood = 481.078.

^aTime-dependent covariate: time during treatment with TLM (0 = no / 1 = yes).

Table 5. Differences between individuals who stopped TLM-treatment and recidivated (treatment withdrawal-recidivism, TWR; n = 13) and individuals who stopped TLM-treatment and did not recidivate (treatment withdrawal-no recidivism, TWnR; n = 6) TLM-treatment.

Variable	TW-R		TW-nR		MDiff	Comparison
	M	SD	M	SD		F	df	η^2p
Previous convictions	8.0	4.8	3.4	4.1	+ 4.6	4.74	1, 17	.22*
Sexual convictions	1.2	1.2	1.7	2.1	− 0.5	0.31	1, 17	.02^ns
Age at first conviction	26.3	14.9	27.2	10.9	− 0.9	0.02	1, 17	.00^ns
Age at index offence	40.9	8.5	38.3	11.3	+ 2.7	0.27	1, 17	.02^ns
Last imprisonment^a	10.3	4.6	13.1	8.7	− 2.8	0.56	1, 17	.03^ns
Age at release	52.9	7.8	51.7	10.8	+ 1.2	0.06	1, 17	.00^ns
Static-99R	5.7	1.9	3.4	2.3	+ 2.3	4.41	1, 17	.21^ns
FTA treatment duration^a	6.4	1.4	6.4	1.4	+ 0.0	0.01	1, 17	.00^ns
Time at risk^a	7.6	2.2	9.6	2.2	− 2.1	3.56	1, 17	.17^ns

Note: M: mean, SD: standard deviation, M_Diff: mean difference (M_Diff = M_+TLM – M_-TLM), df: degrees of freedom.

^a In years.

* p < .05; **p < .01; ***p < .001.

Data availability

The data that support the findings of this study are available from the corresponding author, JS, upon reasonable request. The data are not publicly available due to restrictions as their containing information that could compromise the privacy of research participants.