‘High’ From Alcohol Linked to Genes
Though it’s well known that the sons and daughters of alcoholics are prone to heavy drinking, researchers have had a hard time pinpointing exactly why.
Some studies suggest that alcoholics’ genes impart a heightened sensitivity to the pleasures of a drink. Other experiments imply that people inherit a physical tolerance: They’re able to hold their liquor, in effect, because they’re less sensitive to the drug’s effects than the average person.
A study published last week may help resolve the confusion.
Researchers at Indiana University School of Medicine measured the effects of alcohol on 116 adult social drinkers, who normally averaged about four drinks a week. Half the subjects had at least two close relatives who were diagnosed as alcoholics; the other half had no known family history of heavy drinking. Both groups were given a dose of alcohol intravenously, equivalent to about two drinks, and asked to rate the drug’s intoxicating effects.
All immediately felt the sensation of the booze. But those with a family history rated their intoxication level as significantly higher than the group without the drinking pedigree. “They appeared to feel the alcohol ‘high’ more intensely, at the beginning of the test,” said Sandra Morzorati, a professor of psychiatry and the study’s lead author.
An hour later, however, the high had faded. Though the level of alcohol in their blood was unchanged, the subjects with a family history of alcoholism had adapted; they now felt no more intoxicated than the others, said Morzorati.
“We think that this could mean that people with a family history develop a tolerance for alcohol because they drink more to maintain the same effect they had earlier,” she said. “That initial high goes away, and they drink more to get the feeling back.”
One reason researchers have had difficulty measuring responses to alcohol is that each person absorbs a drink at their own rate: In some the alcohol moves from the stomach to the brain quickly; in others it takes more time. Morzorati got around this problem by administering the alcohol intravenously, and monitored blood alcohol levels continually. “This allows for a direct comparison of the effects, at a specific blood alcohol level,” said Robert Pihl, an alcoholism researcher at McGill University in Montreal.
Genes may underlie how we think about the sensations of drinking, researchers say. In previous studies, people closely related to alcoholics have shown themselves to be very sensitive to positive sensations, such as euphoria, and less to negative effects, such as tiredness, Pihl said. By contrast, those with no family history of alcoholism appear more likely to report the negative sensations, he said.
About one in 10 Americans who drink regularly go on to develop habits that cause them serious problems, and about one in 20 become heavily dependent, alcoholic drinkers, according to government statistics. An estimated 20% to 25% of sons or brothers of alcoholics develop serious drinking problems; and about 5% of alcoholics’ daughters or sisters do.
“The next step in research is to look at the genetic contribution to drinking behavior,” Morzorati said. “To see, for example, if those with a family history enjoy the drug more if they’re drinking faster.”
