"People with mild to moderate alcohol disorders can be treated with medications or behavioral therapy with a primary care doctor," he says. "But many people can do this on their own without having a professional. The idea is teaching people how to reevaluate their drinking."
In the national survey, about half of the people who'd had an alcohol-use disorder recovered, enabling them to drink at low-risk levels without symptoms of dependence. "Some people are uncomfortable with that," Prescott says. "It's a safer prescription to tell someone to quit. But the studies suggest that a large proportion of people are able to cut down and aren't out-of-control."
Other clues can also presage alcohol problems -- and should be taken into account when people assess their alcohol consumption:
* Young age at first drink. Perhaps because of changes in the still-developing brain and because they associate with peers who are also heavy drinkers, people who drink at age 15 or younger are at particularly high risk of developing an alcohol problem. The national survey found that nearly half of people who become alcohol-dependent do so by age 21 and 75% by age 25.
* Flushing reaction to alcohol. Some people carry a gene mutation -- ALDH2 -- that affects alcohol metabolism and causes them to turn red when they drink. Seen mostly in people of Asian descent, the gene is linked to a higher risk of alcohol-use disorders but, conversely, the uncomfortable flushing effect often dissuades these people from drinking.
* Low sensitivity to alcohol. Some people need to drink more to feel an effect compared with the typical person -- often referred to as the ability to "drink everyone else under the table." At least five genes are thought to be linked to this proclivity. An estimated 40% of children of alcoholics carry this trait.
* Specific gene mutations. They include a mutation of the 5HTT gene, which is linked to low serotonin levels in the brain and is found in 60% of people who were alcoholics at age 40, and a mutation of the GABA (A) gene that is linked to a low sensitivity to alcohol.
* The presence of behavioral, emotional or psychiatric disorders -- or smoking dependence.
Any of these factors, when combined with a pattern of exceeding drinking limits, should help people gauge their personal risk, experts say.
Dr. Marc Schuckit is director of the Alcohol and Drug Treatment Program at the Veterans Affairs San Diego Healthcare System, which has revolutionized what is known about genetic influences of alcohol, particularly the concept of low sensitivity. He says genes are responsible for about 60% of the risk of alcohol-use disorders and environmental factors account for the other 40% -- and the two factors conspire to create alcohol-use disorders.
"It's theoretically possible to take kids before they first drink, find out whether they have any gene variations, and say to them, 'If you choose to be a drinker, then be careful because it's very likely that you'll need to drink more to have the same effect," he says.
Based on the growing knowledge of risk factors, experts at the National Institute on Alcoholism and Alcohol Abuse and other policy-setting health organizations say Americans' drinking habits should be screened during visits with their primary-care doctor or during emergency room visits.
"From what we know from scientific studies, there are some very clear things that can be done," Willenbring says. "But people don't ordinarily think of looking to science for how to improve drinking problems."
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If you need help
For more information on assessing personal drinking patterns and cutting back on alcohol, go to www.Rethinking Drinking.niaaa.nih.gov, a website of the National Institute on Alcohol Abuse and Alcoholism, or call (301) 443-3860.
For professional help, contact the American Society of Addiction Medicine at (301) 656-3920 or go to www.asam.org.
Information for health professionals, titled "Helping Patients Who Drink Too Much," can be found at www.niaaa.nih .gov/guide.