High school IQ predicts alcohol use patterns in midlife, study finds

A recent study published in Alcohol and Alcoholism reveals a surprising link between intelligence in adolescence and drinking habits later in life. Researchers found that individuals with higher IQ scores in high school were more likely to be moderate or heavy drinkers as adults compared to those with lower IQ scores.

Alcohol consumption is a widespread behavior with varying health consequences. Excessive drinking is linked to severe health issues, including liver disease, stroke, and cancer. Identifying early predictors of alcohol use can help in understanding risk factors for harmful drinking patterns and guide preventative interventions.

IQ, often assessed through standardized tests, is a strong predictor of various life outcomes, such as education, income, and health. Previous studies have shown mixed results regarding its relationship with alcohol use. While some research had suggested that individuals with higher IQs consume more alcohol, other studies indicated a higher likelihood of abstinence. The researchers behind the new study hypothesized that social and economic factors might explain these discrepancies and sought to clarify the role of adolescent IQ in predicting midlife drinking patterns.

The study utilized data from the Wisconsin Longitudinal Study, a long-term project initiated in 1957 to track over 10,000 high school seniors from Wisconsin. The original purpose of the study was to investigate the aspirations and socioeconomic circumstances of these students. Over the decades, this dataset has expanded, providing a wealth of information on various aspects of participants’ lives, including their cognitive abilities, socioeconomic factors, and health behaviors.

The final sample for this study included 6,300 participants who met specific criteria: they had completed IQ testing during high school, provided self-reported alcohol consumption data in 2004, and reported no history of liver disease. IQ was measured in high school using the Henmon-Nelson Test of Mental Ability, a 90-item, 30-minute assessment evaluating spatial, verbal, and mathematical intelligence. The sample consisted of predominantly White individuals born between 1938 and 1940, and a majority had achieved at least a bachelor’s degree by midlife.

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Alcohol consumption was assessed during the 2004 survey wave, nearly five decades after the participants completed high school. Drinking patterns were classified as abstinence (no alcohol use), moderate drinking (1–59 drinks per month for men and 1–29 for women), or heavy drinking (≥60 drinks per month for men and ≥30 for women). Participants were also asked to report the number of binge-drinking episodes (five or more drinks in one sitting) over the past 30 days.

The analysis controlled for several factors that might influence the relationship between IQ and alcohol consumption, including sex, parental income, and high school class size. These variables were chosen because they reflect socioeconomic and environmental conditions during adolescence. Additionally, the researchers examined two potential mediators: education level and household income in midlife. Education was categorized by the highest degree attained, while household income was measured in thousands of dollars.

Higher IQ scores in high school were associated with an increased likelihood of being a moderate or heavy drinker in midlife. Specifically, each one-point increase in IQ raised the odds of moderate or heavy drinking by approximately 1.6%. However, IQ did not predict whether an individual was more likely to be a moderate drinker versus a heavy drinker, suggesting that the association applies broadly to alcohol consumption rather than its intensity.

In contrast to its association with general drinking patterns, IQ was inversely related to binge drinking. Individuals with higher IQs reported fewer instances of consuming five or more drinks in one sitting over the past 30 days. This finding suggests that while higher-IQ individuals are more likely to drink alcohol, they are less likely to engage in hazardous drinking behaviors.

“We’re not saying that your IQ in high school controls your destiny,” said senior author E. Sherwood Brown, a distinguished teaching professor of psychiatry at UT Southwestern Medical Center. “But IQ levels could lead to intervening social factors that influence drinking, and it’s an important mechanism to explore. Higher IQ seemed to predict a greater likelihood of being a moderate or heavy drinker but not a binge drinker.”

The mediation analyses revealed that household income partially explained the relationship between IQ and drinking patterns. Higher IQ scores were associated with greater household income in adulthood, and increased income was, in turn, linked to higher alcohol consumption. Education, on the other hand, did not significantly mediate this relationship. While higher education levels were associated with greater IQ and more frequent drinking, they did not fully account for the observed patterns.

“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,” said study co-author Jayme Palka, an assistant professor of psychiatry.

Men were more likely than women to drink moderately or heavily and reported more binge-drinking episodes overall. Additionally, participants from larger high school classes, which often reflect urban settings, were more likely to be heavy drinkers. These findings align with broader research suggesting that alcohol consumption is influenced by cultural and environmental norms, such as the greater availability and social acceptance of alcohol in urban areas.

In addition, the study found that higher parental income during adolescence was associated with a greater likelihood of moderate or heavy drinking in adulthood. This relationship may reflect early exposure to social drinking norms or greater access to alcohol. Interestingly, parental income was also associated with fewer binge-drinking episodes, suggesting a complex interplay between socioeconomic factors and drinking behaviors.

Despite its contributions, the study has some limitations to consider. The sample lacked racial and ethnic diversity, as nearly all participants were White individuals born in Wisconsin around 1939. This homogeneity limits the generalizability of the findings to more diverse populations. Additionally, the reliance on self-reported alcohol consumption could introduce bias or inaccuracies.

The study also did not differentiate between alcohol preferences or diagnose alcohol use disorder, which would provide a clearer picture of harmful drinking patterns. Future research could address these gaps by including more diverse populations, exploring the role of life satisfaction, and examining the long-term health impacts of alcohol consumption.

The study, “IQ in high school as a predictor of midlife alcohol drinking patterns,” was authored by Natalie Druffner, Donald Egan, Swetha Ramamurthy, Justin O’Brien, Allyson Folsom Davis, Jasmine Jack, Diona Symester, Kelston Thomas, Jayme M. Palka, Vishal J. Thakkar, and Edson Sherwood Brown.