In earlier work, Ruscio and Borkovec (2004) addressed some (but not all) of the issues discussed above, by individually matching pairs on overall worry severity (based on their Penn State Worry Questionnaire scores; PSWQ; Meyer, Miller, Metzger, & Borkovec, 1990), with one of each pair meeting GAD criteria (as assessed using the Generalized Anxiety Disorder-Questionnaire; GAD-Q-IV; Newman et al., 2002), while the other did not. The gene discussed is GAD1; the disease is generalized anxiety disorder.