Investigators from the Yale School of Medicine and the University of Vermont assessed the alcohol intake of 28 daily marijuana users who voluntarily abstained from pot for a period of eight days.

"Seventeen of the 28 participants (61 percent) increased their alcohol use," researchers reported.

In particular, investigators reported that daily marijuana users with a history of "past alcohol abuse or dependence" substituted alcohol to a much greater degree than those without such a diagnosis. Seven of the 28 participants in the study reported previous problems with alcohol dependence.

Researchers reported that especially light drinkers were also likely to experience an uptick in alcohol consumption while abstaining from cannabis.

"Another subgroup of daily marijuana users that especially substituted alcohol was comprised of those who consumed alcohol at levels below the median number of drinks (per) day during the baseline period," authors wrote. "This finding ... suggests that marijuana users who are also moderate alcohol drinkers should be advised before initiating marijuana abstinence that although their alcohol use might not be problematic, they are still at high risk for increasing their alcohol use."

For more information, please contact Paul Armentano, NORML Deputy Director, at: paul@norml.org. Full text of the study, "Daily marijuana users with past alcohol problems increase alcohol consumption during marijuana abstinence," will appear in Drug and Alcohol Dependence.