Table 1 summarizes the standardized variance component estimates for genetic, shared environmental, and non-shared environmental influences (i.e., h2, c2, and e2, respectively) on conduct disorder. These studies are quite consistent in showing that genetic influences account for a modest to moderate amount of the variance in conduct disorder. In one large study of 5600 individuals from male-male and female-female twin pairs who were ascertained from a population-based registry, there was also evidence that common environmental factors accounted for a significant (32%) proportion of the variance in conduct disorder (Kendler et al., 2003) mirroring the results of the Polderman et al. (2015) meta-analysis of broad conduct disorder phenotypes.
