Personality and neuropsychological function in violent, sexual and arson offenders

We aimed to test the hypothesis that incarcerated offender populations will not differ in neuropsychological test performance if patients are matched on age, intelligence and personality profile, particularly if impulsive aggressive traits and confounds such as substance misuse and performance anxiety are controlled for. 27 violent offenders, 20 sex offenders and 13 arson offenders detained in maximum security hospitals completed dimensional assessments of personality function and were assessed on a battery of frontal and temporal neuropsychological tests. All patients completed a variety of self-report measures of cognitive, affective and behavioural dispositions relevant to offender populations. Trait impulsivity was further assessed and composite impulsivity scores were derived. Assessments of emotional state were administered prior to neuropsychological testing. All patients met the criteria for a DSM-III-R personality disorder diagnosis. There were no significant group differences in age, IQ, or educational attainment. There were no differences in the personality profile of the offender group although sex offenders scored higher on trait anxiety, depression and tension measures. Groups did not significantly differ in their performance on neuropsychological tests apart from poorer perseverative error scores on the Wisconsin Card Sort Test in arsonists, which could not be accounted for by state anxiety or depression scores.