Third, the degree to which the abuse/dependence of individual psychoactive substances indexed the externalizing genetic common factor differed dramatically across substances (Kendler et al. 2007). In both males and females, DAD and AAD strongly, and ND moderately, reflected this genetic common factor. By contrast, in both sexes, CaD poorly indexed the genetic risk to the externalizing spectrum. It is intriguing to ponder the degree to which this difference arises from innate pharmacological features of the drugs themselves versus how they are viewed and controlled by our society (Courtwright, 2001).
