Scientists discover a hidden warning sign of cannabis addiction

Researchers at NYU Langone Health found that people who use cannabis in multiple forms have notably higher rates of daily use and cannabis use disorder. The study, published August 8 in Addictive Behaviors, analyzed responses from 17,732 adults who had used cannabis in the preceding month, drawn from the 2022-2023 National Survey on Drug Use and Health.

The research team identified four consumption patterns. Nearly half of users, 48 percent, primarily smoked cannabis. Another 21 percent combined smoking and vaping, 17 percent mainly consumed edibles, and 14 percent used cannabis in nearly every available form, which researchers called the "polymodal group."

Roughly half of polymodal users reported daily cannabis use, compared with 28 percent of primary smokers, 31 percent of those who smoked and vaped, and 13 percent of edible users. The differences in cannabis use disorder rates were even larger. About 67 percent of polymodal users met criteria for the disorder, compared with 47 percent of smokers-plus-vapers, 36 percent of primary smokers, and 15 percent of edible users.

"Our findings suggest that using cannabis in multiple forms may be a red flag for heavier use and symptoms of addiction," said Omar El-Shahawy, MD, PhD, MPH, assistant professor in the Department of Population Health at NYU Grossman School of Medicine. "Asking patients not only whether but how they use cannabis could help clinicians identify when a fuller assessment may be warranted."

Young adults ages 18 to 25 made up nearly one-third of both the smoking-and-vaping group and the polymodal group. Women represented more than half of edible users, and this method was particularly common among college graduates. Cannabis smokers were more likely to also smoke cigarettes than those who mainly vaped or consumed edibles.

The researchers emphasized that the study establishes an association between consumption patterns and cannabis use disorder rather than proving that multiple-form use directly causes addiction risk. The observational design cannot determine causation, and participants may not have reported their consumption accurately or completely.