A variety of genetically influenced characteristics may also contribute to the increased risk for substance dependence and other externalizing disorders seen in adulthood, such as ASPD. This study provides some support for this hypothesis through the identification of several sites in the genome that may harbor genes for antisocial behaviors. Analyses of multipoint variance component LOD scores for the dichotomous DSM-III-R phenotypes of ASPD and ASPD/CD revealed six locations, on chromosome 13 for ASPD and on chromosomes 1, 3, 4, 14, 17 and 20 for ASPD/CD that had a LOD score of 2 or above. Only some genetic loci were found to be in common for the two heritable phenotypes (ASPD, ASPD/CD) in this American Indian population. This may be somewhat explained by prior findings in twins where it was demonstrated that genetic influences that contributed to the risk for adult antisocial behaviors also contributed to those same behaviors in childhood but that additional genetics risk factors came into play in adolescence and adulthood that could ultimately result in ASPD and alcohol dependence (Jacobson et al., 2002; Lyons et al., 1995).
