Acquired Sociopathy: A Neuropsychological Study of Executive Dysfunction in Violent Offenders

The current research investigated the extent of executive function deficits in a population of 25 violent offenders. The population was separated into primarily instrumental and primarily reactive offenders based on their offence characteristics. Each group was then administered neuro-psychological measures which were considered sensitive to executive function impairment. It was hypothesised that there would be evidence of executive dysfunction in the sample and that in comparison with the primarily instrumental group, the primarily reactive group would show significant impairment on the executive function measures. The results supported these hypotheses; the primarily reactive group was significantly impaired on tasks that assessed higher-order executive functions. The primarily instrumental group was largely intact on executive function measures, although it showed a tendency to be selectively impulsive on several executive function measures depending on how important the task was judged to be. These results suggested that primarily reactive offenders may have difficulty controlling their behaviour (acquired sociopathy) while primarily instrumental offenders may choose not to control their behaviour (selective impulsivity) and may not benefit from behaviourally based treatment. In order to effectively assess and treat violent offenders, consideration of type of violence and integrity of executive function may be important to improve outcomes.