Brain pathology in pedophilic offenders: evidence of volume reduction in the right amygdala and related diencephalic structures.

CONTEXT: Pedophilic crime causes considerable public concern, but no causative factor of pedophilia has yet been pinpointed. In the past, etiological theories postulated a major impact of the environment, but recent studies increasingly emphasize the role of neurobiological factors, as well. However, the role of alterations in brain structures that are crucial in the development of sexual behavior has not yet been systematically studied in pedophilic subjects. OBJECTIVE: To examine whether pedophilic perpetrators show structural neuronal deficits in brain regions that are critical for sexual behavior and how these deficits relate to criminological characteristics. DESIGN: Amygdalar volume and gray matter of related structures that are critical for sexual development were compared in 15 nonviolent male pedophilic perpetrators (forensic inpatients) and 15 controls using complementary morphometric analyses (voxel-based morphometry and volumetry). Psychosocial adjustment and sexual offenses were also assessed. RESULTS: Pedophilic perpetrators showed a significant decrease of right amygdalar volume, compared with healthy controls (P = .001). We observed reduced gray matter in the right amygdala, hypothalamus (bilaterally), septal regions, substantia innominata, and bed nucleus of the striae terminalis. In 8 of the 15 perpetrators, enlargement of the anterior temporal horn of the right lateral ventricle that adjoins the amygdala could be recognized by routine qualitative clinical assessment. Smaller right amygdalar volumes were correlated with the propensity to commit uniform pedophilic sexual offenses exclusively (P = .006) but not with age (P = .89). CONCLUSIONS: Pedophilic perpetrators show structural impairments of brain regions critical for sexual development. These impairments are not related to age, and their extent predicts how focused the scope of sexual offenses is on uniform pedophilic activity. Subtle defects of the right amygdala and closely related structures might be implicated in the pathogenesis of pedophilia and might possibly reflect developmental disturbances or environmental insults at critical periods.

Pedophilia is linked to reduced activation in hypothalamus and lateral prefrontal cortex during visual erotic stimulation.

BACKGROUND: Although pedophilia is of high public concern, little is known about underlying neural mechanisms. Although pedophilic patients are sexually attracted to prepubescent children, they show no sexual interest toward adults. This study aimed to investigate the neural correlates of deficits of sexual and emotional arousal in pedophiles. METHODS: Thirteen pedophilic patients and 14 healthy control subjects were tested for differential neural activity during visual stimulation with emotional and erotic pictures with functional magnetic resonance imaging. RESULTS: Regions showing differential activations during the erotic condition comprised the hypothalamus, the periaqueductal gray, and dorsolateral prefrontal cortex, the latter correlating with a clinical measure. Alterations of emotional processing concerned the amygdala-hippocampus and dorsomedial prefrontal cortex. CONCLUSIONS: Hypothesized regions relevant for processing of erotic stimuli in healthy individuals showed reduced activations during visual erotic stimulation in pedophilic patients. This suggests an impaired recruitment of key structures that might contribute to an altered sexual interest of these patients toward adults.