(NPR) - If one glass of wine takes the edge off, why not drink a few more?

This thinking may help explain the findings of a new study that points to an increase in drinking among adults in the U.S., especially women.

"We found that both alcohol use and high-risk drinking, which is sometimes called binge-drinking, increased over time," says Deborah Hasin, a professor of epidemiology at the Columbia University Medical Center and an author of the study.

To assess drinking trends, researchers conducted face-to-face interviews with thousands of adults. Researchers asked a series of questions, such as: Did you ever drink four or more drinks on an occasion, and if so, how often? The study compares the findings from two surveys. One was carried out in 2001-2002; the other was from 2012-2013.

So what's behind the increase? The study wasn't designed to answer this question, but Hasin says there could be a combination of factors.