Central nervous changes in social dysfunction: autism, aggression, and psychopathy.

Neurodevelopmental disorders such as autism and schizophrenia involve social interaction problems and poor mentalizing abilities, associated with abnormal regional cerebral activity. Similar problems may be present in aggressive personality disorders and psychopathy. This paper reviews brain imaging data from research aiming at establishing possible central nervous correlates to aggression and psychopathy. Studies in this field are associated with a range of method problems. Differences between criminal offenders and controls may be confounded by a number of factors unrelated to personality traits or aggression per se. Phenotypical characterisation varies between studies as do the laboratory methods and their interpretation. In spite of these problems, there are some recurrent findings in the present literature. Hypoactivity or structural reduction of the prefrontal cortex is a consistent finding in violent offenders or subjects with antisocial personality disorder. When defined as a personality disorder of social interaction and empathy, psychopathy seems to be associated rather with central abnormalities in the limbic circuitry. Indications of an increased dopaminergic neurotransmission relative to the serotonergic have also been connected to such personality traits, especially to the AD/HD-related behavioural aspects. Further studies using strict phenotypical definitions or experimental models are clearly warranted to establish a pathophysiological background to destructive personality traits and the propensity to violent acting out.