One potential mechanism of risk transmission is level of response to alcohol, which refers to the subjective intensity of the effects of consuming alcohol. This response varies among individuals (Schuckit, Tipp, Smith, & Bucholz, 1997b) and may account for up to 60% of variance in hereditary alcohol dependence risk (Schuckit, 1999). This construct is particularly relevant because an individual with a low level of response to alcohol is likely to consume more alcohol on any given occasion (in order to obtain the desired effects) and is therefore at greater risk for developing an alcohol use disorder (AUD; Schuckit & Smith, 1996; Ray, Hart, & Chin, 2011; though see Newlin & Thomson, 1990). Given strong evidence for an association between the S allele and alcohol risk, it is likely that S carriers exhibit a low level of response. However, some studies have found that the LL genotype is associated with a low level of response to alcohol (Hu et al., 2005; Schuckit et al., 1999), indicating that more work is needed. To our knowledge, no studies have directly assessed level of
