Predictors of Young Adult Antisocial Behavior and Psychopathic Personality among Swedish Twins

Psychopathic personality (also known as sociopathic personality and antisocial personality) refers to “individuals who have a manipulative interpersonal style, lack empathy and remorse, and lack the ability to consider the consequences of their behaviour” (Forsman et al., 2010, p. 45). The hypothetical construct of psychopathic personality implies enduring characteristics that predict antisocial behavior.

However, research is needed to determine whether measures of psychopathic personality actually add to prediction of antisocial behavior, over and above prediction from earlier antisocial behavior. To test prediction of young adult antisocial behavior from earlier measures of both antisocial behavior and psychopathic personality, Forsman et al. (2010) analyzed longitudinal associations of CBCL/6-18 ratings of 2,255 Swedish twins at ages 8-9, 13-14, and 16-17; YSR ratings at ages 13-14 and 16-17; ABCL and ASR ratings at ages 19-20; and the Youth Psychopathic Inventory (YPI) completed by the twins at ages 16-17 and 19-20. Early antisocial behavior was measured by summing ASEBA Rule-Breaking and Aggressive Behavior scores for ages 8-9 and 13-14. Mid-adolescent antisocial behavior was measured by summing these scores at ages 16-17. And young adult antisocial behavior was measured by summing the ABCL and ASR scores at ages 19-20. Forsman et al. found that ages 16-17 YPI scores for psychopathic personality added a significant but very small amount (1.7%) of unique variance to prediction of antisocial behavior at ages 19-20 and that age 16-17 variance shared by the YPI and ASEBA scales predicted an additional 5.8% of variance.

However, age 16-17 ASEBA scores alone accounted for much more variance (18.9%) in the age 19-20 antisocial behavior scores than the YPI’s unique or shared variance. When developmentally persistent antisocial behavior was measured by combining the ASEBA scores from ages 8-9, 13-14, and 16-17, the age 16-17 YPI scores still accounted for a significant but small amount of variance in age 19-20 scores. However, the ASEBA scores for developmentally persistent antisocial behavior significantly predicted not only antisocial behavior, but also YPI scores at ages 19-20, over and above prediction from age 16-17 YPI scores. Analyses of monozygotic vs. dizygotic twin data showed that genetic variance in age 16-17 YPI scores uniquely accounted for more variance (6.7%) in age 19-20 ASEBA Rule-Breaking than Aggressive Behavior (1.8%) scores. The complex developmental interplays between psychopathic personality-as measured by the YPI-and antisocial behavior-as measured by the CBCL, YSR, ABCL, and ASR-suggest that early antisocial behavior outweighs psychopathic personality in predicting young adult antisocial behavior. Although adolescent YPI scores significantly added to the prediction of antisocial behavior- especially as measured by the ASEBA Rule-Breaking syndrome- Forsman et al. suggested that early “antisocial behavior evokes psychopathic personality, which in turn starts having an independent influence on antisocial behavior” (p. 45).

Reference: Forsman, M., Lichtenstein, P., Andershed, H., & Larsson, H. (2010). A longitudinal twin study of the direction of effects between psychopathic personality and antisocial behaviour. Journal of Child Psychology and Psychiatry, 51, 39-47.