it has been linked to genes putatively underlying EXT spectrum disorders, particularly alcoholism. Williams et al. (1999) found that reduced P3 amplitude and an alcoholism diagnosis were jointly linked to a region on chromosome 4 near the alcohol dehydrogenase gene (ADH3), and Hill et al. (1998) found an association between lower P3 amplitude and presence of the dopamine receptor A1 allele in children from alcoholic families.
