(Fowler et al., 2007). Although twin and adoption studies offer some of the most compelling evidence for genetic risk, interpretation of findings should always consider that an assumption of equal environments is being made in terms of the influence of environmental factors on a trait for twin or sibling pairs. Also, as previously mentioned, adolescents represent a distinct group of drinkers, insomuch as studies evaluating diagnostic levels of alcohol involvement may be limited in their ability to adequately identify problematic drinkers due to the criteria being less appropriate for youth.
