Given the scarcity of the literature in this area, the first priority in this line of research is to attempt to replicate our findings in another genetically informative female sample. The next logical step is to test for gender differences in heritability of PTSD and its genetic overlap with AD in a civilian sample of men and women. Studies in this area are of particular interest in light of the absence of evidence of gender differences for other anxiety disorders (Hettema et al. 2005; Kendler et al. 2003) and mixed evidence for depression (Bierut et al. 1999; Franic et al. 2010). It is also important to address potential distinctions in both the link with AD and the relative contribution of genetic factors to childhood versus adulthood trauma exposure and PTSD onset. With respect to identifying populations at high risk for substance-related problems, it is also important to determine the extent to which our findings generalize to other substances of abuse.
