"Social anxiety disorder (SAD) and alcohol use disorders (AUDs) are frequently comorbid (see Morris, Stewart, and Ham (2005), for a review). Approximately 13% of adults with past-year SAD met criteria for a comorbid AUD, and of adults with lifetime SAD, 48.2% met criteria for an AUD (Grant et al., 2005). This relationship appears to be due to a greater likelihood of having comorbid alcohol dependence (characterized by tolerance, withdrawal, or compulsive alcohol consumption (APA, 2000); OR = 2.26 to 2.7) rather than alcohol abuse (characterized by a pattern of negative consequences that result from alcohol use (APA, 2000); OR = 1.2 to 1.23; Buckner, Timpano, Zvolensky, Sachs-Ericsson, & Schmidt, 2008; Grant et al., 2005). Both retrospective and longitudinal studies have shown that when SAD and AUD co-occur, SAD typically precedes the onset of the AUD (Buckner, Schmidt, et al., 2008; Buckner, Timpano, et al., 2008; Buckner & Turner, 2009; Falk, Yi, & Hilton, 2008).

"Consistent with studies of adults, Kushner and Sher (1993) found that 43% of college freshmen with SAD met diagnostic criteria for an AUD while only 26% of college freshman without SAD met criteria for an AUD. Overall, however, research on the relationship between social anxiety and alcohol use among college students has revealed very mixed findings (see Morris et al. (2005), for a review). Some laboratory studies have demonstrated that socially anxious participants drink more in anticipation of both interaction (Higgins & Marlatt, 1975) and speech tasks (Kidorf & Lang, 1999), whereas others (e.g., Holroyd, 1978) have found that socially anxious students drink significantly less alcohol than non-socially anxious peers during informal laboratory-based “get togethers.” Survey studies of college students have either failed to find a relationship between social anxiety and alcohol consumption, or have found an inverse relationship between social anxiety and alcohol consumption (e.g., Buckner, Schmidt, & Eggleston, 2006; Gilles, Turk, & Fresco, 2006; Ham & Hope, 2006; Lewis et al., 2008). One possible reason for the lack of a positive relationship between social anxiety and alcohol use is that socially anxious students may avoid social situations and only use alcohol to cope with anxiety in social situations when they cannot be avoided (Norberg, Norton, & Olivier, 2009; Stewart, Morris, Mellings, & Komar, 2006).

"Despite the fact that many studies have found a negative relationship, or no relationship at all, between social anxiety and alcohol use, A.R. Schry, S.W. White / Addictive Behaviors 38 (2013) 2690–2706 2691many studies have found that social anxiety is positively associated with ARPs (e.g., Buckner, Ecker, & Proctor, 2011; Buckner & Heimberg, 2010; Buckner et al., 2006; Gilles et al., 2006; Norberg et al., 2009). A significant relationship between social anxiety and ARPs may be particularly important, because AUDs are defined by problems resulting from the use of alcohol rather than simply the quantity and frequency of use (Buckner et al., 2006). However, not all studies have found a significant relationship between social anxiety and ARPs (e.g., Ham, Zamboanga, Bacon, & Garcia, 2009; LaBrie, Pedersen, Neighbors, & Hummer, 2008)."

Source

Schry, Amie R, and Susan W White. “Understanding the relationship between social anxiety and alcohol use in college students: a meta-analysis.” Addictive behaviors vol. 38,11 (2013): 2690-706. doi:10.1016/j.addbeh.2013.06.014