any drinking was: (0) Less than once a month or never, (1) Approximately once or twice a month, (2) Once a week, and (3) A couple of times a week or more often. These variables have been used in earlier analyses of drinking behaviors in the Finnish twin cohort data (Dick et al., 2011; Latvala et al., in press; Pagan et al., 2006; Rose et al., 1999; Viken et al., 1999).
