ALDH2*2 has been related to alcohol sensitivity as measured by retrospective self-reports of flushing and other symptoms (e.g., headaches, heart palpitations, drowsiness) following low doses of alcohol (Chen et al., 1998; Matsuo et al., 2006; Takeshita and Morimoto, 1999; Takeshita et al., 2001), as well as by retrospective self-ratings of heightened level of response to alcohol (Hendershot et al., 2009; Wall et al., 1999). These data are consistent with alcohol administration studies, which have found ALDH2*2 relates to heightened physical (e.g., flushing, pulse rate, hormonal changes, EEG reactivity) and subjective (e.g., feeling great, drunk, dizzy) responses to alcohol (Cook et al., 2005; Luczak et al., 2002; Minami et al., 2002; Wall and Ehlers, 1995; Wall et al., 1992; 1994). These heightened responses to alcohol are found even at low doses of alcohol, with possession of two ALDH2*2 alleles resulting in even more intense responses than possession of one ALDH2*2 allele (Peng et al., 1999; 2002).
