Earlier drinking may mean more drinking problems

The minimum legal drinking age of 21 now in place by all U.S. states may have prevented a significant amount of alcoholism and drug abuse, according to a new study.

In the study, researchers found that adults living in states that permit the purchase of alcohol before age 21 were more apt to have alcohol and drug problems later on than adults living in states that prohibit people under the age of 21 to buy alcohol.

The study, published today in an early online edition of Alcoholism: Clinical and Experimental Research, suggests that lower drinking ages may lead to more problems with alcohol and drugs later in life.

"It seems plausible that frequency and intensity of drinking in late adolescence may have long-term effects on adult substance use patterns," Dr. Karen Norberg, of Washington University in St. Louis and colleagues note in the report.

It's highly possible, they add, that the higher legal drinking age may help keep a lid on the amount of alcohol consumed before age 21. Until the mid-1980s, many states allowed people to purchase alcohol at the age of 18. However, all states now have a minimum drinking age of 21 because of a 1984 federal law that used eligibility for funding to pressure for the change.

Norberg and colleagues found differences in rates of alcoholism and drug abuse among 33,869 U.S. adults exposed to different minimum legal drinking age laws.

A little more than half of the adults studied (52 percent) would have been allowed to purchase alcohol before their 21st birthday, the investigators note.

After adjusting for factors that might skew the results, the researchers found that people who lived in states that permitted buying and drinking alcohol before age 21 were about 30 percent more likely to have suffered from alcoholism and 70 percent more likely to have had a drug problem in the past year. (For comparison, about 10 percent of all of the people studied met criteria for alcohol abuse in the past year, and about 3 percent met criteria for marijuana or other illegal drug abuse in the past year.)

This was true even among people evaluated in their 40s and 50s.

Norberg and colleagues calculate that had the minimum legal drinking age been set at 21 in all states throughout the 1970s and 1980s, the prevalence of alcohol and substance abuse disorders among adults born in the U.S. between 1948 and 1970 would have been nearly 15 percent lower than that recorded over the past 20 years.