et al., 2000; Kim et al., 2006; Samochowiec et al., 2006; Sery et al., 2006). However, some data suggest that alcoholic sub-phenotypes may associate with specific COMT diplotypes (Enoch et al., 2006; Kweon et al., 2005; Tiihonen et al., 1999; Wang et al., 2001). Thus, genes that alter impulsivity contribute to risk for alcoholism and other mental diseases that have overlapping psychopathology.