Aggressive Antisocial Behavior: Risk Factors and Personality Profile

Sammanfattning: Background: There is an increasing knowledge that violent criminality is restricted to a group of individuals with early onset of behavioral problems. These problems often emerge in combination with substance abuse and evolve into an antisocial personality disorder when the individual reaches adulthood. This type of multifaceted problem can be defined as aggressive antisocial behavior (AAB). Aim: The aims of this thesis were to determine the occurrence of AAB in the Swedish nation-wide general population, investigate the risk factors of AAB, identify the personality profile of individuals with AAB, and study the association between personality traits and level of AAB. Methods and results: In a Swedish register study on violent crime convictions (1973–2004), including 2.5 million individuals, 4 % of the population was convicted at least once for a violent crime (AAB), of which almost one in four were persistent. They were characterized by male gender (90 %), early onset of criminality, personality disorders, substance use disorders, and a high rate of criminal recidivism. In two cross-sectional prison studies all study groups showed a common personality pattern, as measured by the Temperament and Character Inventory, deviating highly from the general population. Females were more deviant than males, and showed evidence of a stronger association between their personality and measures of trait aggression. A similar pattern in 9 and 12 year old children with AAB was found in a register study of Swedish twins, but with less pronounced gender differences. A salient pattern of low character maturity (Self-Directedness and Cooperativeness) combined with an extreme temperament (high Novelty Seeking and low Reward Dependence) emerged in all groups, where impulsiveness, sensation seeking and disorderliness together with detachment, insensitivity and independence from others were associated to AAB. Conclusion: A mature character with strong self-governance and capability to cooperate meaningfully with others emerged as important protective factors against AAB, which is why these personality traits appear to be promising targets for interventions.