The neuropsychology and neurology of sexual deviance: a review and pilot study

Current neurological hypotheses of paraphilia posit that sexual deviance is associated with frontal and/or temporal lobe damage. This broad conception is based on few investigations, however, and the first goal of this study was to review the existing data derived from neuropsychiatry, neuroimaging and neuropsychology. It is concluded that although fronto-temporal dysfunctions are sporadically reported among sexual offenders, the evidence is scarce and it might not be specific to this type of offending. The second objective of this investigation was to gather preliminary neuropsychological data with more homogeneous subgroups of sexual offenders. A profile of lower-order executive dysfunctions (e.g. sustained attention and inhibition) and verbal deficits with intact or good capacities for higher-order executive functioning (e.g. reasoning and cognitive flexibility) and visuo-spatial processing was preferentially found among sexual offenders, suggesting basal fronto-temporal anomalies. Importantly, pedophiles were more consistently and severely impaired than rapists of adults. However, this basal fronto-temporal profile is not characteristic of sexual deviance, as it is also found in association with delinquency and criminality in general. Future neuropsychological and brain imaging studies should consider subgroups of sexual offenders and recruit non-sexual violent persons and non-violent individuals in order to disentangle the complex relations between brain anomalies and sexual deviance.