The study, by researchers at Washington University School of Medicine in St. Louis, is available online and will be published in the February 2012 issue of Alcoholism: Clinical & Experimental Research.
“After Prohibition, most states had a drinking age of 21,” says senior author Richard A. Grucza, PhD, assistant professor of psychiatry at Washington University School of Medicine. “In the late 1960s and early 1970s, as voting rights were extended to 18-year-olds, and people of that age were drafted to serve in Vietnam, a lot of states lowered their drinking ages. But by the late 1970s, we saw spikes in deaths related to driving under the influence (DUI) among young people, and states began to revert to a drinking age of 21.”
In 1984, a federal law set the U.S. legal drinking age at 21.
Grucza said he and his colleagues had earlier observed higher rates of alcohol and drug use problems among adult men and women born in states that allowed alcohol sales to youth under age 21. Other shorter-term studies had found higher rates of DUI accidents, other drinking behaviors, suicides and homicides in states with lower drinking ages during the time those laws were in effect.
“So studying the longer-term effects of drinking ages on suicide and homicide was a logical next step,” he says.
Grucza and his co-authors used data from the U.S. Multiple Cause of Death files, 1990-2004, along with data on living populations from the U.S. Census and American Community Survey. The combined data contained records on more than 200,000 suicides and 130,000 homicides for individuals who turned 18 between 1967-1989, when the legal drinking ages were in flux.
“In this study, we found that youth who lived in states with lower drinking ages remain at elevated risk for suicide and homicide as adults,” Grucza says. “The effect seems to be specific for women.”
Grucza said suicide and homicide are very different phenomena.
“Female homicide victims are killed by acquaintances in 92 percent of cases. “Lower drinking ages elevate rates of alcohol problems, which may contribute to alcohol-fueled domestic violence. For suicide, alcohol may contribute to the severity of suicide attempts. In general, women attempt suicide more often than men, but men are more likely to complete – or die from – suicide. Alcohol problems may tip the balance by turning attempts into completions more often. This would be particularly risky for women because of their higher number of suicide attempts.”
Many scientists say the adolescent brain is especially vulnerable to the effects of drugs, including alcohol, Grucza says.
“We saw drinking-age changes as a ‘natural experiment’ to see what happens to young people who have easy access to alcohol compared to those whose access is restricted,” he says. “If early drinking is a true risk factor for alcoholism, we would see multiple adverse long-term consequences among people who lived under more permissive drinking age laws as youth – and we did.”
Grucza says the study’s results help to solidify the case for drinking-age laws.
“The 21 minimum legal drinking age was adopted to reduce the number of DUI-related accidents and other social consequences of drinking involving young people,” Grucza says. “The finding that it may also save lives and reduce problems during adulthood shows the importance of maintaining these laws and developing other interventions aimed at reducing drinking among young people.”
Grucza RA, Hipp PR, Norberg KE, Rundell L, Evanoff A, Cavazos-Rehg P, Bierut LJ. The Legacy of Minimum Legal Drinking Age Law Changes: Long-Term Effects on Suicide and Homicide Deaths Among Women. Alcoholism: Clinical & Experimental Research, online Nov. 15, 2011.