In a study involving identical and non-identical twins, researchers conducted telephone interviews with 1,213 sets of male-male twins, average age 50. The researchers' goal was to better understand the hereditary and environmental effects on developing alcoholism -- not by studying the twins themselves, but by interviewing the twins' children (ages 12 to 26) and the mothers of those children.
Although there is little question in the medical community of hereditary transmission of alcoholism risk, there have been very few studies from this offspring-of-twins perspective. With this angle, the researchers hoped to gain insight into both genetic and environmental risk factors based on the twin's history of alcoholism. Interviewing twin families allowed them to collect information about psychiatric disorders including parental alcoholism and determine whether or not the children were being raised in a low-risk environment with no alcoholism present.
That data revealed 276 of the children had fathers without any type of alcohol dependence or abuse. However, the rest of the children either had a father or uncle with an alcoholic disorder.
Thus researchers found those children with alcohol disorders in the family were significantly more likely to exhibit alcoholism than those offspring of nonalcoholic fathers.
Researchers also state that the occurrence of alcohol use is at its highest during the adolescent to young-adult year, so the minors interviewed may not have passed through this high-risk period. However with the passing of time, those at low-risk for alcoholic disorders would eventually adapt a pattern of nonproblematic drinking. Conversely, those at higher risk would show more drinking problems.