The first twin study of alcoholism was conducted in Sweden in the 1950’s by Kaij (1960). This study used birth records and Temperance Board registration data to identify alcoholic male twins from Skåne, Sweden. Kaij conducted followup interviews with alcoholic twins and their co-twins,3 showing that twins having at least one Temperance Board registration exhibited a fivefold increase in probability of being diagnosed as alcoholic, thereby confirming the validity of registrations as a measure of alcohol problems. He also noted, however, that those twins with social problems were likely to be overrepresented among Temperance Board registrants.
