Interference inhibition in offending and non-offending pedophiles: A preliminary event-related fMRI study

The ability to inhibit behavior is thought to be an import skill for avoiding criminal conduct, especially when combined with personal predispositions or criminogenic needs such as a pedophilic preference disorder. While previous research emphasized the relationship between impulsivity and child sexual offending, not pedophilia per se, studies on the underlying neurobiological mechanisms in subdomains of impulsivity remained scarce. Here, we focused on interference inhibition and examined event-related functional magnetic resonance imaging (fMRI) data of three groups of men performing a color-word Stroop task: (1) pedophiles with a history of CSO (P+CSO, n = 11), (2) pedophiles without a history of CSO (P-CSO, n = 8) and (3) non-pedophilic, non-offending healthy controls (HC, n = 10). On the behavioral level, P+CSO revealed increased Stroop interference as compared to P-CSO and HC. Moreover, increased Stroop interference in P+CSO was accompanied by enhanced conflict-related activity in left superior parietal cortex and precentral gyrus as compared to P-CSO. Albeit behavioral analyses of error and post-error processing revealed no significant between-group differences, P-CSO showed increased post-error-related activity in left posterior cingulate, precuneus and middle temporal gyrus as compared to P+CSO. Our preliminary data highlight inhibition deficits in offending as compared to non-offending pedophiles or healthy men and suggest that functional alterations in attention reallocation and impulse suppression/control may moderate the risk for committing CSO in men suffering from pedophilia.

An Exploratory Study on the Central Nervous Correlates of Sexual Excitation and Sexual Inhibition

The Sexual Inhibition/Sexual Excitation Scales (SIS/SES) measure sexual excitation and sexual inhibition proneness. We used SIS and SES scores of 62 heterosexual teleiophilic men (M_age 34.3, SD = 9.9) to predict brain activation levels during the presentation of male and female visual sexual stimuli in a magnetic resonance imaging (MRI) scanner. Statistical analyses revealed significant correlations. SES and SIS1 scores were positively associated with brain activation in various brain regions during the presentation of both male and female stimuli. SIS2 turned out to be a weaker predictor of brain activation, still revealing one significant correlation in the right lateral orbitofrontal cortex. Significant regions for SES and SIS1 were, among others, primary and supplementary motor areas, the caudate nucleus, the dorsal anterior cingulate cortex, anterior insula, and prefrontal areas. Our study can be seen as an exploratory investigation of SIS and SES with means of functional brain imaging. The results provide a promising contribution to the assertion of neurophysiological systems of sexual inhibition and excitation proneness.

Approach and Avoidance Tendencies Toward Picture Stimuli of (Pre-)Pubescent Children and Adults: An Investigation in Pedophilic and Nonpedophilic Samples

The presence of pedophilic sexual interests is considered of high importance for predicting recidivism among individuals who have committed sexual offenses. However, objective and valid assessment methods that are robust against confounding issues such as cognitive capacity and manipulation are sparse. We applied the Approach-Avoidance Task (AAT) for detecting sexual interests in 38 pedophilic men (18 primarily attracted to boys) and 27 male nonpedophilic (11 gay) participants. The AAT relies on automatic approach and avoidance tendencies, independent of cognitive abilities such as memory capacity and intelligence. Approach-avoidance tendencies toward stimuli depicting seminude prepubescent boys and girls as well as men and women are reported. The results were consistent with previous research on the utility of the AAT: Except for pedophiles attracted to girls, the mean AAT scores (approach minus avoidance reaction time for each stimulus category) were positive only for stimuli of the preferred category. A multivariate binary logistic regression approach revealed 80% overall accuracy in differentiating pedophilic from nonpedophilic participants.

Gray matter anomalies in pedophiles with and without a history of child sexual offending

Pedophilia is a psychiatric disorder that is inter-related with but distinct from child sexual offending (CSO). Neural alterations reportedly contribute to both pedophilia and CSO, but until now, no study has distinguished the brain structural anomalies associated with pedophilia from those specifically associated with CSO in pedophilic men. Using high-resolution T1-weighted brain images and voxel-based morphometry, we analyzed the gray matter (GM) volume of the following 219 men recruited at four acquisition sites in Germany: 58 pedophiles with a history of CSO, 60 pedophiles without any history of CSO and 101 non-pedophilic, non-offending controls to control for the effects of age, education level, verbal IQ, sexual orientation and the acquisition site. Although there were no differences in the relative GM volume of the brain specifically associated with pedophilia, statistical parametric maps revealed a highly significant and CSO-related pattern of above vs below the 'normal' GM volume in the right temporal pole, with non-offending pedophiles exhibiting larger volumes than offending pedophiles. Moreover, regression analysis revealed that the lower GM volume of the dorsomedial prefrontal or anterior cingulate cortex was associated with a higher risk of re-offending in pedophilic child molesters. We believe our data provide the first evidence that CSO in pedophilia rather than pedophilia alone is associated with GM anomalies and thus shed new light on the results of previous studies on this topic. These results indicate the need for new neurobehavioral theories on pedophilia and CSO and may be potentially useful for treatment or prevention approaches that aim to reduce the risk of (re)offending in pedophilia.