Parents sometimes look upon teen drinking as a harmless rite of passage. But new research suggests it has a darker side, one that can last a lifetime.

"Not only are people who start to drink at a younger age more likely to develop 1/8lifelong alcohol dependence, but they are more likely to be injured, to be in motor vehicle crashes and to be in fights," said Ralph Hingson, director of the U.S. National Institute on Alcohol Abuse and Alcoholism's division of epidemiology and prevention research.

"Many people regard alcoholism as a middle-age person's problem," he added. "But you can develop quite severe problems when you are quite young."

Hingson led a study, published recently in the journal Pediatrics, in which his team found that early dependence on alcohol often meant continued trouble with drinking later in life.

In their study, Hingson and his colleagues analyzed the results of a survey done in 2001 and 2002 by the U.S. National Institute on Alcohol Abuse and Alcoholism. The survey included interviews with more than 43,000 people over the age of 18.

Next, Hingson's team focused on just the 4,778 people who appeared to have been alcoholics at some time in their lives.

Of those who were ever alcohol-dependent, 15 percent appeared to become dependent before age 18, the researchers found, and 47 percent became hooked before the age of 21. In all, two-thirds became dependent before age 25.

"We were the first to report 1/8in a previous study3/8 that the younger people are when they start, the more likely they are to develop alcohol problems," Hingson said. "That's why it's so important to identify the problem among young people."

Echoing Hingson's advice, in early March the U.S. Surgeon General's Office issued a "call to action" on underage drinking, appealing to Americans to do more to stop the nation's 11 million current underage drinkers from using alcohol.

The call to action includes recommendations not only for government and school officials but also for parents, other adults and young people themselves.

Parents should work with their schools and other programs to prevent and reduce underage drinking, the Surgeon General's office suggested. They should also ask their underage children if they are drinking and discuss the problem frankly, Hingson said.

And parents should not shrug off underage drinking as "a phase," added David Rosenbloom, professor of public health at Boston University's School of Public Health and director of Join Together, an organization that supports drug and alcohol prevention and treatment programs in communities.

The Hingson research, he said, "shows very clearly that the earlier someone starts drinking, the more likely that person is to develop alcohol dependence and the more likely he is to have adverse consequences."

"Someone who doesn't start drinking until age 19 or 20 almost never becomes an alcoholic," noted Rosenbloom, citing research.

When teens starting drinking, their judgment is clearly lacking, Rosenbloom said. "We know now the adolescent brain goes through rapid growth, and the last part 1/8to develop is3/8 judgment and restraint."

"The thinking is also that early alcohol use may have long-lasting effects on how the brain actually develops," Rosenbloom said. "That's not set in stone yet," he noted, but parents may want to mention it as they talk to their kids.