The Neuropsychological Determinants of Sexual Crimes

When the mechanisms that lead to sexual crimes are examined, the biological basis of human sexuality should be taken into consideration. So far, however, the neuropsychological mechanisms of sexual perversion are not fully understood, nor has the neuropsychological profile of a sexual abuser been determined. Structural and functional brain anomalies are thought to play a crucial role in sexual offenders; the literature points to the importance of the brain mechanisms responsible for stimulation, direction and control of the sex drive. Empirical data shows that brain damage occurs in nearly 50% of perpetrators. The aim of this article is to identify the brain mechanisms of sexual drive disorders, modelled on sexual dysfunctions in frontal syndrome, the Klüver-Bucy Syndrome and temporal lobe epilepsy. We have also collected and systematised the existing neuropsychological and neuroimaging research on sexual abusers. First, we demonstrate the relation between sexual deviations and nervous system disorders on the general level (lower IQ in paedophiles and sexual sadists, comorbidity of paraphilias and other mental disorders). Secondly, we introduce three hypotheses of specific, and particularly localised, neuropsychological dysfunctions in sexual offenders. The Frontal-Dysexecutive Theory points to behavioural disinhibition and other cognitive aspects of behaviour control as the main causal factors. The Striato-Thalamo-Frontal Theory, claims that there is a shared pathological brain mechanism in sexual deviance and obsessive-compulsive disorders. The Temporal-Limbic Theory suggests that hyperactivation of sexual arousal and impaired erotic discrimination are the causal factors in sexual abusers.