Three general conclusions can be gleaned from this overview of the twin literature on conduct disorder. First, familial influences account for much of the variance in conduct disorder. At the aggregate level, there are moderate levels of genetic and shared environmental influence on conduct disorder symptomatology and diagnoses; however, for individual clinical DSM-IV criteria there is variation in the relative influence of genetic and environmental factors. Second, the heritability of conduct disorder increases over time, and is attributable, in part, to new genetic influences that emerge across development. Third, conduct disorder shares genetic influences with other forms of disinhibitory behavior, and does not have unique genetic influences. These general principles from latent genetic studies of conduct disorder have implications for efforts to identify its measured genetic variants.
