New findings from the NIH’s National Institute on Drug Abuse (NIDA) show that the prevalence of cannabis use disorder (CUD) among American adults, both male and female and across multiple age groups, has increased significantly in recent years, while the prevalence of alcohol use disorder (AUD) has remained stable and even declined a bit in some subgroups over the same period.

One of the most important take-home messages of the study, published in JAMA Psychiatry, is that the increase in CUD prevalence and severity among U.S. adults who use cannabis directly “challenges the notion that cannabis has low addictive potential,” according to the paper’s authors. The senior author was Nora D. Volkow, M.D., NIDA’s Director, a world authority on drug abuse, a pioneer in the science of addiction, and a member of BBRF’s Scientific Council.

The study was based on responses of 186,823 individuals aged 18 or older who participated in the National Surveys on Drug Use and Health (NSDUH) between 2021 and 2024, an interval that captures the period immediately following the COVID pandemic. NSDUH provides nationally representative data on cannabis and alcohol use, as well as CUD, AUD, and their severity, with the latter defined according to criteria in the DSM-5 diagnostic manual. “Moderate-to-severe disorder” in this schema is characterized by the presence of four or more CUD or AUD symptoms. Results of the surveys are understood to underestimate AUD and CUD, since by design they do not sample those in the armed forces or institutionalized populations—including people in prisons and healthcare institutions who are using substances and/or being treated for addiction and related health conditions.

By any accounting, problematic alcohol use remains the most prevalent substance-use issue, even with the number of U.S. adults with AUD as measured by the NSDUH declining between 2021 and 2024 from 28.8 million to 27.1 million. With about 265 million adults in the U.S., this means the fraction with AUD was in 2021 and still remains above 10%.

In the same 2021-2024 interval, adults with CUD increased nearly 27%, from 15.3 million to 19.4 million, according to the NIDA survey. That’s an increase from roughly 5.8% of U.S. adults to 7.3%. This clear trend paralleled trends of increasing cannabis potency, expanding cannabis legalization, and a decreasing public perception of cannabis-related harm to users, Dr. Volkow and her NIDA colleagues and co-authors observe.

Looking within the overall numbers at subgroups, the researchers noted that the steepest increases in the prevalence of CUD and of moderate-to-severe CUD occurred among both males and females aged 35-49 and males 50 and older.

By contrast, AUD and moderate-to-severe AUD declined among males aged 21-34, and total prevalence of AUD declined among females in the 21-34 and 35-49 age brackets. “This divergence may reflect behavioral and cultural shifts,” the team wrote, “including increasing cannabis preference over alcohol,” as well as possible declines in binge or heavy drinking.

This is not to minimize either the damage or the future risk posed by alcohol use. Across all age groups, about 2 adults in 3 of both sexes report past-year alcohol use and about 3 in 4 among 21-34 year-olds. Abuse of alcohol is by no means uncommon. While AUD generally declined in the 2021-24 period, in the 21-34 group, the decline was from 20% to 17%, still over 11 million young people. AUD in males ages 35-49 remained stable (15.1%-15.7%) in the period, while in females in fell from 11.1% to 8.9%.

The oldest age bracket, covering those 50 and above, showed stable AUD prevalence in both sexes, but a completely different pattern with respect to cannabis. CUD in the 50+ group rose from 2.4% to 3.8% among males (a 50% increase). Moderate-to-severe CUD, while less common, rose at an even faster pace, doubling to 1.2% in males over 50 and increasing sevenfold to 0.7% in females over 50 between 2021 and 2024.

The investigators said that findings of the survey “repudiate conventional assumptions that cannabis carries a low addiction risk and that most young adults with CUD have mild symptoms.” In 2024, past-year cannabis use was reported by about 30% of males and females ages 18-20, and over 37% of males 21-24. Perhaps most important, “among those who used cannabis, 45.8% to 50% had CUD and of those with CUD, 51% to 61% had moderate-to-severe CUD. This means that CUD among cannabis users in that age group was more than twice as prevalent as AUD was among those who used alcohol.

One possible reason behind this pattern, the team said, is increasing potency of the primary addictive component of cannabis, THC, with high-potency products becoming easier to access and finding considerable acceptance on the part of users. “CUD is associated with adverse physical, cognitive, and psychosocial outcomes, including suicidality, violence, and psychoses (especially in young men),” the team said. And even though moderate-to-severe CUD “warrants clinical treatment, treatment rates have declined alongside expanding cannabis legalization” and an increasing perception that cannabis has benefits, they added.

“The high prevalence of moderate-to-severe CUD underscores the importance of early detection, routine screening, timely access to and sustained engagement in evidence-based CUD treatment, and targeted strategies to counter increasing acceptance, availability, and potency of cannabis products,” the team wrote.

Dr. Volkow had these comments on the significance of the new study: “These findings are an important reminder that cannabis is not a harmless substance and can lead to addiction. We are seeing this rise cannabis use disorder and its severity, including among older adults, at a time when cannabis products contain higher concentrations of THC, access has expanded, and fewer people perceive cannabis use as harmful. These trends reinforce the need for routine screening for cannabis use disorder and continued research on prevention and treatment, including the development of effective medications.”