2002; Porjesz et al., 2005; Rangaswamy et al., 2002), 3) presence in unaffected relatives of those with a disorder (Begleiter, Porjesz, Bihari, & Kissin, 1984; Hill, Muka, Steinhauer, & Locke, 1995; Rangaswamy et al., 2004), and 4) in currently unaffected individuals, association with later development of an EXT spectrum disorder (Berman, Whipple, Fitch, & Noble, 1993; Carlson, Iacono, & McGue, 2004; Hill, Steinhauer, Locke-Wellman, & Ulrich, 2009; Iacono et al., 2002).
