He's a common character in American movies and low-brow fiction — the scruffy, middle-aged, alcoholic man who looks back on a mountain of disappointment through the bottom of a cocktail glass. Think Ray Milland in "The Lost Weekend," or, if you're younger, Nicolas Cage in "Leaving Las Vegas."

Trouble is, he's an anachronism. Today, the real-life, alcohol-dependent American is increasingly likely to be a woman. At least she's catching up quickly to take her place alongside the timeworn stereotype, says Richard A. Grucza, PhD, assistant professor of psychiatry. "What an alcoholic looks like has changed," he says.

Two recent studies by Grucza and his colleagues reveal startling shifts in the epidemiology of alcoholism. "Although we might not think of a 35-year-old woman as the template for alcohol dependence, heavy alcohol use at younger ages, combined with greater alcohol use by women, means alcoholics are different now than in the past," Grucza says.

The first study by Grucza looked at groups at the same point in their lives but with birth dates 10 years apart. The data came from large, national epidemiological surveys, one conducted in 1991 and 1992, and the second a decade later. Statistical examination of results from the two surveys revealed that though men showed only slight increases in their rates of drinking and alcohol dependence, women showed a significant increase in drinking and problems with alcohol.

Specifically, the results say that women born later, particularly those born after 1944, were 1.2 times as likely to drink as women born before them and, more strikingly, those who drank were at 1.5-fold higher odds to become alcohol dependent at some point in their lives compared with the women born earlier. Essentially, the results show that the gender gap as it relates to alcohol use and abuse is narrowing.

Research conducted by Richard A. Grucza, PhD, and Karen E. Norberg, MD, research instructor in psychiatry, shows an increase in alcohol use by women.

Provocatively, the timing of the increase coincides largely with the advent of the so-called "Baby Boom" generation and with many of the advances made by women. "There's been a great deal of social, economic and political progress for women in the years since World War II," says Grucza. "It seems there also may be a downside to some of the advances in terms of the risk for problems such as alcohol dependence."

He points to troubling indications that women may not be seeking treatment for their addictions as diligently as they might. Also of concern are serious health effects of alcoholism specific to the female gender. It's possible, Grucza says, that because of their generally lower body weight, women may have more serious health consequences from excessive drinking. In addition, they have lower levels of alcohol dehydrogenase in their digestive tracts, which means they are not able to metabolize alcohol as quickly or efficiently as men. Women alcoholics also have been shown to lose more years of life to their addiction than men. And, perhaps most alarmingly, alcohol use is an established risk for developing breast cancer. He says the information about increased alcohol use among women has consequences for health care providers who need to pay attention to the alcohol intake of their young, female patients.

Grucza's study also showed that the increase in drinking among women born in the 1940s was not simply a spike but persisted into the next age cohorts as well, diminishing only slightly among those born most recently.

Interested in understanding the mechanics of the increases, Grucza went back to the surveys to examine data for the reasons why. "We've known for a long time that the earlier you start drinking, the higher your risk of developing alcohol dependence," he says. That marker, known as the age at onset of drinking (AOD), became the focus of his next study.

And the results of the analysis were consistent. In fact, women born before 1944 pretty consistently began to drink at roughly age 20 if they drank at all. But for the generation born immediately after World War II — the early Baby Boomers again — the AOD dropped precipitously, by slightly more than three years to approximately age 17. From other studies, Grucza says, it's widely accepted that if a person begins drinking at 21 or older, his or her risk of becoming alcohol dependent is about one in 10. For those who begin to drink at age 17 or younger, the lifetime risk more than triples, to roughly one in three.

Grucza warns not to think of early AOD as a direct cause of developing alcohol dependence. The causes are complex and include influential genes mixed with environmental factors, a propensity for impulsive behavior, and an emerging theory in the neuroscience community that says that when an adolescent's brain, which is still developing, is exposed to alcohol, the results are different from those in an adult, with permanent effects on addictive behavior. It's also important to note that 29 states lowered their drinking ages between 1970 and 1975, when many of the women in these studies were taking their first drinks.

But something important is going on, because, as Grucza explains, age at onset changed over a short period of time and so did dependence, and in the same people. "And genes don't change that fast," he says. Offering hope for intervention, he adds, "Whatever it is that leads to alcohol dependence has been changing. And whatever the causal factors are, if they're changing, they can be modified."

Carolyn E. Sartor, PhD, right, and Arpana Agrawal, research assistant professor of psychiatry, study the role of genetics and environment in alcohol use and dependence.

In separate work exploring the question of the relative importance of genetics and environment as causal in alcohol use and dependence, Carolyn E. Sartor, PhD, and her colleagues have shown that the influence of genetics increases as young women transition from taking their first drink to becoming alcoholics. Sartor, a postdoctoral research fellow, says that although environment is most influential in determining when girls begin to drink, genes play a larger role as women advance to problem drinking and on to alcohol dependence.

Sartor's team studied female twins, ages 18 to 29, to ferret out the influences of genes and environment through the many stages of drinking behavior. Environmental factors shared by the twins (exposure to conflict at home or alcohol use among peers, for example) exerted the largest influence on initiation of alcohol use. But the results also show that all transitions in drinking behavior were attributable in part to genetic factors, increasing from 30 percent for the timing of the first drink to 47 percent for the speed at which they progressed from problem drinking to full-blown alcohol dependence.

But genetics did not explain everything. "Even when genetic factors were most influential, they accounted for less than half of the influence on drinking behavior, Sartor says. "That's good news in terms of modifying these behaviors and reducing the risk of developing alcohol dependence. Genetics are not destiny, and our findings suggest that there are opportunities to intervene at all stages of alcohol use."

While Grucza's and Sartor's studies have sounded alarms, boosting awareness of these causal factors and avoiding risky behaviors could limit or reverse this unhealthy trend.

Jim Dryden contributed to this article.