The findings of a recent study in JAMA Psychiatry suggest dramatic increases – approaching 50% – in the prevalence of alcohol use disorders in the United States. But the study’s methodology has come under scrutiny: The data sets that the researchers used might be too different for reliable comparison.

The JAMA Psychiatry research, led by Bridget F. Grant, PhD , of the National Institute on Alcohol Abuse and Alcoholism, analyzed data from two waves of the National Epidemiologic Survey on Alcohol and Related Conditions ( NESARC ), a cross-sectional, federal survey administered during 2001-2002, known as Wave 1, and during 2012-2013, known as Wave 3 (JAMA Psychiatry. 2017 Aug 9. doi: 10.1001/jamapsychiatry.2017.2161 ). The findings were stark: In addition to a sharp increase in the rate of 12-month alcohol use and high-risk drinking, Dr. Grant and her associates found that the rate of DSM-IV alcohol use disorder climbed from 8.5% of the population during the first wave to 12.7% of the population during the third.

But Richard A. Grucza, PhD , an addiction-medicine researcher who has studied and written about these trends extensively (Addiction. 2007 April;102[4]:623-9 ), told that he doesn’t buy the new findings.

“I would urge caution in drawing conclusions based on only two time points,” Dr. Grucza said. Comparing those two waves of data is inherently problematic, he explained.

“The NESARC made important changes between 2001-2002 and 2012-2013 – and several of these changes could be expected to lead to higher rates of disclosure,” said Dr. Grucza, a professor of psychiatry at Washington University in St. Louis. “This would lead to apparent increases in a variety of things – for example, they saw a 100% increase in prevalence of marijuana use among adults. So, the problem isn’t with the 2012-2013 NESARC, per se, but in the comparison between the 2012-2013 NESARC and the 2001-2002 NESARC.”

The changes include differences in the way each wave of the data was collected. The 2001-2002 survey was conducted using U.S. Census Bureau employees and didn’t offer participants incentives for survey completion. The 2012-2013 NESARC, however, was conducted through a private contractor; in addition, participants provided biological samples and received modest cash incentives for completing the survey.

“We can only speculate, but [the collection of DNA through samples of saliva] might make the participants think that their drug use would be known – and that they might therefore disclose it, anyway,” Dr. Grucza said. “I would guess that they would have been assured that this wasn’t the case during the informed consent process, but that process tends to be long, and people don’t pay attention to the whole informed consent document.”

The NESARC findings differed substantially from those found by the National Survey on Drug Use and Health ( NSDUH ), a federal survey of people aged 12 or older released annually by the Substance Abuse and Mental Health Services Administration. The NSDUH gathers data first in a screening phase and then in an interview phase; data are gathered in the interview phase through computer-assisted, self-administered interviews. Dr. Grucza said countless studies “suggest people respond more faithfully when disclosing to a computer as opposed to a live interviewer.”

According to the NSDUH, the rate of past-month use of alcohol fell slightly in 2015 from the previous year’s rate and was comparable to the estimates in 2005-2013.

However, Dr. Grant pointed out that substantial changes made to the questions on the 2015 NSDUH also make comparisons to previous years problematic. As a result, she said, the “NSDUH is not able to estimate the trends during the time period analyzed in the NESARC,” Dr. Grant said. “We stand by the reliability and validity of our survey data.”

For his part, Robert L. DuPont, MD , said it’s important to look at the data broadly. “The bigger picture is that alcohol is the most commonly used addictive substance by Americans, and there is evidence of increased problems resulting from drinking. For example, alcohol liver disease and cirrhosis of the liver are rising in adults and have been described as one of a group of ‘diseases of despair,’ along with suicide and drug overdose deaths,” said Dr. DuPont, the first director of the National Institute on Drug Abuse and the president of the Institute for Behavior and Health in Rockville, Md. “The fundamental message is that alcohol (and drug use) patterns show complexity that has significant public health importance. Alcohol use and related problems are more complex than a bumper sticker stating that they are either ‘up’ or ‘down.’ ”

Dr. Grucza, Dr. Grant, and Dr. DuPont had no conflicts to disclose.