NeMUP research initiative

Neural mechanisms underlying pedophilia and sexual offending against children:
origins, assessment, and therapies


Epidemiology and etiology

Empirical forensic studies in Germany have found that about 2.8% of boys and 8.6% of girls are victims of severe sexual assault. Further investigations showed that approximately half of the sexual offenders have a sexual preference for children through a pedophilic sexual preference.
Criminological research assumes that this population represents only a small fraction of actual perpetrators, because sexually offending children comes only rarely to accusation or conviction.
The high prevalence of sexual victimization and the accompanying publicity stand in contrast to the limited empirical data. Also, the clinical support situation for therapeutic prevention of sexual assault is moderate, at best.
In particular, neurobiological investigations are seldom. Additionally, the existing publications suffer from methodological problems such as sample selectivity and low case numbers in the forensic context and hence as such do not present a clear picture.
Initial results from early studies highlight genetic predisposition, developmental incidents, social learning, and brain morphology as potential causes for pedophilia.
Furthermore, studies dealing with neuropsychology, personality, sexual development, and sexual physiology suggest a relationship between early brain developmental disorders, pedophilia, and child sexual abuse.
It remains open, however, whether aethiopathogenetic influences are the reason for the development of a sexual preference disturbance on the one hand and the disturbance in sexual behavior on the other.

Abnormalities in brain structure

The hypothesis that brain developmental disorders are a cause for pedophilia has been supported by recent imaging studies, reporting changes in the amygdala and connected areas responsible for sexual development. The reported differences in volume could constitute evidence for intrinsic environmental or developmental disabilities, as they could be triggered, for example, by drastic adverse experiences in critical stages of development.
Additional support for the hypothesis that changes in brain structure are the basis of sexual disorder in behavior is that the observed changes show a statistically significant relation to delinquent behavior. More morphological abnormalities were found in the prefrontal cortex (PFC), ventral striatum, medial temporal cortex and two main fiber bundles. So far, however, these results are very inconsistent and are in urgent need of critical review. The extent of these changes being the cause of pedophilia and / or child sexual abuse is not yet clear.

Abnormalities in brain function

Functional brain studies point to changes in the processing of emotional and sexual stimuli associated with pedophilia.
Pedophilic subjects showed a decreased response of the amygdala, hypothalamus and prefrontal cortex upon presentation of sexual stimuli with adult bodies schemas compared to non-pedophilic subjects. Taken together, it can be understood that presentation of preferred stimuli (children or adults) leads to activation of largely the same brain areas in all persons (pedophiles or teleiophiles).


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