A teenager's IQ could be oddly predictive of their beverage choices later in life, and scientists don't know why that is.
According to a new study of predominantly White men and women in the US, the higher someone's IQ score is in their first year of high school, the greater chance they have of regularly drinking alcohol in adulthood.
In the analysis, IQ scores, which measure a person's general intelligence, could predict whether teenagers were more likely to be drinkers than abstainers in mid-life, though not whether their drinking was more likely to be moderate or heavy.
For women, moderate drinking was defined as 1–29 alcoholic beverages a month, and for men, it was defined as 1–59 beverages. Heavy drinking was considered anything over that.
The study included health, education, and financial information from 6,300 men and women in the state of Wisconsin, who graduated from high school in 1957.
In 2004, 48 years after graduating, participants reported how many alcoholic beverages they had consumed in the past month, plus the number of times they had consumed five or more alcoholic beverages in one session, considered 'binge-drinking'.
For every one-point increase in IQ score, researchers found a 1.6 percent increase in being a moderate or heavy drinker as opposed to an abstainer.
Those with higher IQ scores, however, were less likely to report binge-drinking episodes.
The results do not necessarily mean that your IQ as a teenager "controls your destiny", explains psychiatrist Sherwood Brown from the University of Texas (UT) Southwestern Medical Center. But it does suggest that IQ scores are linked to social factors that may influence drinking in mid-life.
When Brown and his colleagues at UT considered socioeconomic factors, they found that household income partially mediated the relationship between IQ and drinking habits, but a person's level of education did not affect this relationship.
"While it's not possible to capture all the underlying mechanisms that mediate the relationship between drinking and IQ, we know that income partially explains the pathway between the two," says neuroscientist Jayme Palka from UT.
Previous studies have also linked higher IQ scores to higher household incomes. In turn, studies have found a relationship between higher incomes and more frequent alcohol consumption, possibly because of the availability of alcohol in this population and "social drinking norms related to prestige/success".
In 2020, an analysis of Norwegian men found that those with higher intelligence scores reported more frequent drinking in their late 20s than those who had lower scores, and binge drinking seemed to be a driver of this association.
But this recent study in the US suggests that may not be true of women.
Binge drinking was ultimately less common among women than men, and among both groups, higher IQ scores predicted less binge-drinking in the future, not more.
However, this new research was conducted among a cohort of predominantly White, non-Hispanic individuals, most of whom were women with a bachelor's degree, which means the results may not apply to other populations.
Researchers at UT argue that future research should consider how alcohol use disorder is related to IQ and explore other mediating factors that could explain the relationship between cognition and drinking.
The study was published in Alcohol and Alcoholism.