Fourth, in both males and females, DA was the strongest index of liability to externalizing disorders and CB was the weakest. This difference was considerably more pronounced in females than in males. These results were partially confirmed by a prior study based on personal interviews in the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders, which found that the genetic risk to externalizing disorders was best indexed in males by (in order) antisocial personality disorder (ASPD), DA, AUD, and conduct disorder (CD) and in females by DA, AUD, nicotine dependence, and ASPD (Kendler and Myers 2013). However, our results are inconsistent with those found by Hicks et al. in their interview-based study where the common factor for externalizing disorders loaded most strongly on, in order, ASPD, AUD and DA (Hicks et al. 2004).
