(HealthDay)—There are fewer problem "potheads" today than before the wave of marijuana legalization that's swept the United States, a new analysis of federal survey data shows.
Researchers found an across-the-board decline in daily or near-daily pot users who could be diagnosed with cannabis use disorder, according to results published in the Dec. 1 issue of Drug and Alcohol Dependence.
This included a 27% decline in problem use among teens; a 30% decline among young adults; and a 37.5% decline among adults 26 and older between 2002 and 2016, the findings showed.
"The number of people with problems, instead of increasing as predicted, has decreased," said senior researcher Dr. Silvia Martins. She is director of the substance use epidemiology unit at Columbia University's Mailman School of Public Health, in New York City.
For the study, her team analyzed data from the annual National Survey on Drug Use and Health, zeroing in on frequent marijuana users. The investigators defined a frequent user as someone who used cannabis at least 300 days during the previous year.
The survey asks questions that can be used to diagnose cannabis use disorder. These include questions about whether someone's use has caused them to develop a tolerance, whether their use has caused social or legal problems, and whether they continue to use despite those problems, Martins said.
The researchers expected that marijuana legalization would result in more people developing a problem with pot.
Instead, they found that the opposite happened—fewer regular users reported that their marijuana habit was wreaking havoc on their lives.
This might be because legalization has made it less likely that users will wind up in jail or in court for smoking pot, Martins said. Legal pot is less likely to cause problems in their life because of legalization itself.
Another possible explanation is that, for many people, marijuana has become equivalent to having a glass of wine or a neat scotch after work, Martins said.
"A lot of these frequent users could be people who come home and smoke one joint a day," she said.
"Usually there are many people using a legal substance and it's only a small portion of people that end up developing the disorder," Martins added. "The people who need treatment are the tip of the iceberg."
The researchers also found significant decreases in regular users who reported driving under the influence of marijuana: 26% fewer teens, 29% fewer young adults, and 38% fewer adults 26 and older.
Addiction experts are skeptical about these findings, however.
For example, the federal survey might have missed some regular users, because it didn't ask specific questions about different types of marijuana use, said Dr. Kara Bagot, medical director of the Addiction Institute of Mount Sinai, in New York City.
"A lot of kids are vaping cannabis, and a good proportion of those kids actually don't even know they are using cannabis," she said, adding that the same problem could arise with regular ingestion of pot edibles.
Dr. Scott Krakower, assistant unit chief of psychiatry at Zucker Hillside Hospital in Glen Oaks, N.Y., agreed.
"I'm more concerned that legalization might result in underestimates, because I think legalization almost normalizes use that would otherwise be problematic," he said. "And even if the statistics are showing some reduction, there is definitely more access, and with higher quality and higher potency of the agents."
There's even some disagreement from an unexpected quarter—Martins' own work.
In another study published recently, Martins and her colleagues found that cannabis use disorder had increased in the first four states to legalize marijuana: Colorado, Washington, Alaska and Oregon.
The rate of problematic use among 12- to 17-year-olds rose from 2.18% to 2.72% after legalization, and it was 25% higher than in non-recreational states, according to findings published online Nov. 13 in JAMA Psychiatry.
Among adults 26 or older, past-month marijuana use after legalization was 26% higher than in non-recreational states. Past-month frequent use rose by 23%, and past-year problematic use rose by 37%.
"Once marijuana becomes more normative, we're going to see a huge increase in people with cannabis use disorder," Martins said.
More information: The U.S. National Institute on Drug Abuse has more about marijuana and addiction.
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