Evidence is mounting in support of a genetic basis for anti-social behavior.

A study of twins, published in June 2005 issue of the Journal of Child Psychology and Psychiatry, revealed that anti-social behavior is strongly inherited in children with psychopathic tendencies such as callousness and reduced emotional capacity.

What Is Psychopathy?

High Risk Children

"[The child] 'does not feel guilty if he has done something wrong, he does not show feelings or emotions, and he is rarely helpful if someone is hurt,' was a teacher's description of one of the 7-year-old subjects of this twin study. The lack of guilt and empathy portrayed captures the core emotional impairment of psychopathic individuals (Viding 2007).

Psychopathy More than APD

Diagnostic criteria for childhood and adult Antisocial Personality Disorder (APD), the clinical diagnosis most closely corresponding to psychopathy, consist primarily of observable antisocial behaviors [such as violence towards or stealing from others]. The criteria for APD diagnosis do not, however, emphasize some of the more subjective essential aspects of the Antisocial Personality [lack of remorse empathy and callousness] (Hare 1999).

Antisocial Kids, Psychopathic Adults

This twin study set out to examine the heritibility of not only antisocial behavior, but also other, less concrete antisocial traits. The importance being that identification of psychopathic traits in youth may allow early intervention, as children who exhibit antisocial behavior in childhood are at high risk for showing antisocial and criminal behavior as adults (Moffitt 2003).

Why Study Twins?

Studies of twins are often used by researchers investigating inherited traits. Identical twins share exactly the same genes, whereas fraternal, or non-identical, twins are no more genetically similar than normal siblings. Although all personality disorders, including as APD, are likely to be impacted by both genetic predispositions and environmental factors, comparing identical and fraternal twins can provide insight into which traits are more strongly influenced by inheritance.

Twin Study of Genetic Basis for Psychopathy

British researchers examined 3687 pairs of 7-year-old twins for callous-unemotional traits (CU) and high levels of antisocial behavior (AB), both early warning signs of life-long psychopathy that can be identified in childhood (Viding 2005).


The sample of twins assessed in this investigation was drawn from a much larger, more general study called the Twins Early Development Study (TEDS).

Although callous unemotional traits (CU) were not directly assessed in TEDS, the researchers were able to design a CU scale by using questions relating to antisocial traits drawn from several assessments. The other measurement, an antisocial behavior (AB) scale, was devised from questions on the Strengths and Difficulties Questionnaire (SDQ) that had been designed to assess conduct problems.

Data were gathered by teachers who used these CU and AB scales to rate the children on anti-social behavior and psychopathic tendencies. Those who scored in the top 10% of the sample for anti-social behavior were separated into two groups, subjects with and without psychopathic emotional tendencies (CU).


Results indicated that callous unemotional traits (CU) are strongly influenced by genetics. Of particular interest, when the assessments of children displaying high levels of AB were sub grouped by those with high and low CU traits, the AB in highly callous unemotional children showed strong genetic influence and was not related to shared environment, whereas AB in children who did not show callous unemotional traits was not as heritable and displayed environmental influence.

Bottom line, children with antisocial traits such as callousness and lack of emotion may be carrying a genetic blueprint for adult psychopathy.

Additional Research on Development of Adult Psychopathy

The results of this study are complimented by a very recent longitudinal study published in August 2007 issue of The Journal of Abnormal Psychology. This study, examining subjects as toddlers and then, 25 years later, as adults, demonstrated that, as early as the age of three, there are temperamental and physiological difference between those who show psychopathic tendencies as adults and those who don't (Glenn 2007).

More Information on Psychopathy

Additional resources on psychopathy, sociopathy and APD include: Psychology Prof Online, The Mayo Clinic: Mental Health Center and the article Antisocial Personality.

This Suite 101.com article summarizes information on two studies of childhood traits that may be antecedents of adult psychopathy. The contents of this article are not meant to be used for diagnosis and are not a substitute for professional help and counseling.

Additional Psychopathy Resources

American Psychiatric Association APA (1994 & 2000) Diagnostic and Statistical Manual of Mental Disorders.

Glenn, A. L. et al (2007). Early Temperamental and Psychophysiological Precursors of Adult Psychopathic Personality. Journal of Abnormal Psychology. 116, 508 - 515

Hare, R. D. (1999) Without Conscience: The Disturbing World of the Psychopaths among Us. Guiford Press.

Moffitt, T.E. (2003). Life-course persistent and adolescence-limited antisocial behaviour. In B.B. Lahey, T.E. Moffit, & A. Caspi (Eds.), Causes of conduct disorder and juvenile delinquency. Guilford Press.

Viding, E., James R., Blair, R., Moffitt, T. E., Plomin, R. (2005). Evidence for substantial genetic risk for psychopathy in 7-year-olds. Journal of Child Psychology and Psychiatry, 46, 6.