Research from adoption, twin and family studies has shown that there is a genetic diathesis in the development of SD [Cloninger, 1987; Mirin et al., 1991; Pickens et al., 1991; Rounsaville et al., 1991; Luthar and Rounsaville, 1993; Merikangas et al., 1998; Tsuang et al., 1998; Kendler et al., 2003; Agrawal and Lynskey, 2008]. Investigations on the genetic liability for SD, in particular MSD, suggest that there are common as well as substance-specific genetic factors [Metten and Crabbe, 1994, 1999; Pickens et al., 1995; Bierut et al., 1998; Tsuang et al., 1998; Grucza and Bierut, 2006; Belknap et al., 2008; Huizink et al., 2010]. And indeed, there are numerous known examples of specific genes known to affect multiple substance use disorders [Gelernter et al., 2006b; Luo et al., 2006, 2007; Yang et al., 2008; Sherva et al., 2010].
