from quantitative and molecular genetic studies reveals the substantial impact of genetic factors in the etiology of ASB. The majority of evidence for a role of genetics is derived from twin studies and, to a lesser extent, adoption studies, and indicates that about half of the variance in ASB can be explained by genetic factors, whereas the remainder can be explained by unique and common environmental factors (Burt, 2009; Polderman et al., 2015; Rhee & Waldman, 2002). Twin studies further determined that the relationship between ASB and cognitive and psychiatric traits is in part due to common genetic factors, indicating there may be shared biological mechanisms underlying these behaviours9,10. Early candidate gene studies identified a number of genetic polymorphisms involved in serotonergic and catecholaminergic function, among others, that may be involved in ASB(Gunter, Vaughn, & Philibert, 2010). However, a systematic review and meta-analysis of the majority of published genetic association studies on aggression and violence failed to reveal a significant overall association between any of the previously reported candidate genes and aggression(Vassos, Collier, & Fazel, 2014). The lack of replication of candidate genes for ASB is consistent with other candidate gene studies in psychiatry, which for the most part have
