Genetic role in alcoholism as strong in women as in men, study of twins finds

Women have as strong an inherited susceptibility to alcoholism as men, according to a report appearing today in the Journal of the American Medical Association.

In recent years, several studies have shown that in men genetics accounts for 50 percent to 60 percent of the factors that determine a person's vulnerability to a severe drinking problem.


The new study shows that the same magnitude holds for women, said Dr. Kenneth Kendler, a psychiatrist at the Medical College of Virginia in Richmond, Va., who led the study.

That makes the genetic influence in alcoholism among women about the same as for hypertension, and somewhat higher than that estimated for coronary artery disease, stroke or major depression.


"It's a very important finding, showing that heritability for alcoholism in women is so high," said Dr. Robert Cloninger, a psychiatrist at Washington University who is director of a multisite study of genetics and alcoholism for the National Institute on Alcohol Abuse and Alcoholism.

The study challenges what had been conventional wisdom among physicians and psychotherapists.

In their research, Dr. Kendler and colleagues used birth records of twins in Virginia to track down 1,080 adult pairs of female twins. Each twin was interviewed by a clinical social worker to determine whether she had ever been dependent on alcohol.

"Alcoholism is not a black-and-white diagnosis," Dr. Kendler said. "At a minimum, you have to say there was a time in your life when, for at least a month, you or people close to you felt you drank too much; not, for example, just over a weekend after a love affair broke up."

Another sign of alcoholism used in the study was loss of control over drinking. "You can't stop once you take that first drink, or you drink more than you wanted or thought you should," Dr. Kendler explained.

Beyond such basic signs of problem drinking, the interviewers also looked for two more serious signs: tolerance, drinking increasingly greater amounts to get the same effect, and withdrawal, getting the "shakes" when drinking stops or drinking in the morning to avoid the shakes.

A final sign of alcohol dependence is impairment. "We asked, 'Did you ever drink so that it interfered with something important, like work or taking care of children?' " Dr. Kendler said.

Based on these interviews, Dr. Kendler and his colleagues found that at every level of alcoholism, identical twins, who are genetic carbon copies of each other, were significantly more likely than fraternal twins to have similar histories of alcoholism, suggesting a strong genetic role.