Some subgroups carry higher vulnerabilities to AUDs and/or SUDs. These include genetically-influenced characteristics of impulsivity or sensation seeking (externalizing phenotypes) and anxiety or depressive symptoms (internalizing characteristics) that enhance the risk for both AUDs and SUDs (Schuckit, 2009; Slutske et al., 2002; Yip et al., 2012). Additional preexisting phenotypes increase the risk for only AUDs, including how a person responds to alcohol (Quinn and Fromme, 2011; Newlin and Renton, 2010). The most widely studied alcohol response characteristic is a low level of response (low LR) to alcohol that reflects the need for a higher number of drinks to experience effects (Chung and Martin, 2009; Schuckit and Smith, 2011; Schuckit et al, 2011, 2012). Other characteristics with higher risks for substance related problems include entering treatment for medical or psychiatric conditions, family histories (FH) of alcohol and/or drug problems, and demographic variables such as Caucasian heritage (Compton et al., 2006; Fein and Landman, 2005; Wagner and Anthony, 2002;Wu et al., 2011).
