Biology, norms, and personality: A developmental perspective

The focus concerns psychobiological risk factors in the development of antisocial behavior among male and female subjects. Using longitudinal data, violent and nonviolent criminal offences were studied in relation to childhood vulnerability indicators, norm-breaking behavior in adolescence, and to personality traits and biochemical measures in adult age. Subsequently, levels of norm-breaking behavior in adolescence were studied as related to personality and biochemical measures in adult age. Data were obtained from a representative group of 82 male and 87 female subjects as (1) teacher ratings of behavior at age 13, assumed to differentially reflect vulnerability to externalizing and internalizing psychosocial disturbances; (2) self-ratings of norm-breaking behaviours at age 1 5; (3) Karolinska Scales of Personality scores and biochemical measures at age 26-27 years, and (4) records for criminal offences up to age 40. In both the male and female groups, criminal offences during the life span were associated with childhood externalizing and adolescent norm-breaking behavior. Furthermore, in the male group, criminal and violent offences were associated with adult psychopathy-related personality traits and a biochemical indicator of psychosocial vulnerability; platelet monoamine oxidase (MAO) activity. Among female subjects, criminal offenders displayed significantly lower MAO activity in comparison to noncriminals. High levels of norm-breaking behavior in adolescence were associated with adult high impulsiveness, low socialization, and low platelet MAO activity in both male and female subjects. The results of the analyses were used as a basis for some theoretical and methodological conclusions.