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Coming to grips with the cycle of violence

Frisell et al.’s (2010) paper is a landmark effort that is sure to be influential and highly cited. It documents the phenomenon of familial transmission of violent behavior in concrete numeric terms using data from a nationwide sample of individuals. It provides compelling support for widely accepted, but still controversial, premises (e.g. concordance for violent behavior among family members reflects constitutional as well as experiential influences). It also presents evidence in support of newer emerging perspectives (e.g. the notion that heritability for specific behavioral proclivities can vary across differing environments – in the current instance, across differing social strata). In addition, it highlights intriguing new points – for example, the notion that particular forms of antisocial deviance (within Frisell et al., specific subtypes of violent crimes) show heightened rates of family transmission, with greater behavioral specificity, than others. 
 
All empirical studies, including this one, have methodological limitations that constrain inferences and interpretations. For example, while the use of matched controls comprises a strength of Frisell et al. (2010), effects of confounds cannot be ruled out entirely in a matched design. In particular, comparisons involving adoptive samples, which were utilized in Frisell et al. to infer genetic contributions to transmission of violence, carry risks of confounding due to the non-randomness of the adoption process (Cadoret, 1985; Billings et al. 1992). However, rather than focus on methodological points here, we focus instead on two major substantive issues highlighted by Frisell et al. (2010). One is the question of what etiologic factors underlie the heightened incidence of violent behavior observed among family members of violent individuals. The other is what can be done to reduce their impact.