Neuroimaging Pedophilia and Fetishism: A Distinct ‘Brainprint’ of Sexual Preference

Abstract

Pedophilia is defined as a persistent sexual interest in prepubescent children and has long been the subject of considerable concern due to its association with sexual offending against children. Despite progress in the neuroscientific understanding of pedophilia, the structural and functional mechanisms underlying it remain unclear, as does its distinctiveness from other paraphilic interests in the brain, which have yet to be investigated using neuroimaging. Additionally, much of the extant research has failed to control for criminality, raising concerns over construct validity. The objectives of this project were to compare non-contact-offending pedophilic men (n=9), fetishistic men (n=15), and teleiophilic men (with sexual interests in sexually mature female adults) (n=16) on measures of brain structure, sexual processing, and self-report tools to better understand the neural underpinnings of pedophilia and, for the first time, compare it to another paraphilia: foot fetishism. Study 1 examined structural maps of gray matter volumes across the brains of our three groups using voxel-based morphometry (VBM), Study 2 utilized diffusion tensor imaging (DTI) to investigate white matter microstructure, and Study 3 used a novel fMRI picture task to compare patterns of functional brain activity when viewing sexually salient paraphilic and non-paraphilic stimuli. Interviews surveyed paraphilic interests, sexual compulsivity, criminality, trauma, and demographic variables. The results of our studies support previous research demonstrating structural and functional differences between pedophilic and teleiophilic individuals, and for the first time distinguished a “brainprint” of pedophilia from that of foot fetishism in exclusively non-contact-offending samples. VBM results demonstrated significantly lower gray matter volumes in the two paraphilic groups across several large, widespread clusters, which were most pronounced in the pedophilic group, particularly in frontal and temporal/limbic regions. DTI results demonstrated significant differences in white matter health between teleiophilic men and the two paraphilic groups, with no differences between men with pedophilia and men with foot fetishism. fMRI results showed unique activity patterns during visual sexual processing of preferred stimuli between all three groups, with significant increases in the overall use of neural resources among both men with pedophilia and men with fetishism. Together, these results open the door for a new line of research on paraphilia.