American Board of Psychiatry and Neurology (ABPN) Practice Exam

The group that most strongly supports the heredity of alcoholism is adopted siblings. This conclusion comes from studies that examine the influence of genetic predisposition on alcoholism independent of shared environmental factors.

When we look at adopted siblings, they share a biological connection with their biological parents, who may have a history of alcoholism, while not sharing any environmental influences from those parents. This allows researchers to isolate the effects of genetics on the likelihood of developing alcoholism.

In contrast, biological siblings and parents share both genetic material and environmental factors, which makes it difficult to determine the extent to which observed behaviors, such as alcohol use and dependence, are due to hereditary influences versus environmental ones. Mothers and daughters may also share these genetic and environmental influences, particularly through social and cultural practices surrounding alcohol use. Thus, adopted siblings present a unique opportunity to analyze the hereditary aspect of alcoholism without the confounding impact of a shared upbringing.