simultaneously in genetic studies. This issue is essentially the same as the potential demographic and cognitive confounds; a well-designed study should be able to specifically attribute genetic influences to the discounting phenotype and in turn to addictive behavior, but not other conditions. Of course, it is also possible that genetic influences may be determined to be more robust with other comorbid conditions. Alternatively, it is entirely plausible that impulsive discounting will be best understood as a risk factor for a number of conditions, not only addictive disorders, but perhaps disorders characterized by poor self-control or perhaps externalizing disorders in general. As a consequence, genetic variation that contributes to impulsive discounting may be risk loci for a more broad domain of psychopathology. In light of these possibilities, it is critical for these collateral characteristics and conditions to be ascertained to examine these relationships empirically.
