The rate of cannabis use disorder (CUD) among frequent marijuana consumers has dropped significantly over the past two decades, according to researchers from Columbia University’s Mailman School of Public Health.
Although cannabis is not physically addictive, a small percentage of users can still struggle with dependency issues, which falls under the classification of CUD. Individuals who are unable to control the amount of pot they consume, struggle to cut down their weed use, or find themselves unable to fulfill major life obligations on account of being too high could be diagnosed as suffering from CUD. This diagnosis could also apply to people who feel that their cannabis use is causing social or interpersonal problems with their friends, family, or co-workers.
In a new study published in the Drug and Alcohol Dependence journal, the authors note that the number of people diagnosed with CUD has been declining between 2002 and 2016. The researchers hypothesized that this reduction only accounted for occasional pot users, and not heavy users. “We expected that CUD prevalence among people reporting daily/almost daily use would not decrease,” the authors wrote.
To test their theory, researchers examined data from annual National Surveys on Drug Use and Health between 2002 and 2016. From the pool of respondents, analysts isolated 22,651 people aged 12 and older who said that they had gotten high at least 300 days out of the past year. Researchers searched the data for annual prevalence of CUD, cannabis dependence or abuse, and examined how these trends developed over time.
After analyzing the data, the research team was surprised to discover that their hypothesis was incorrect.
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“Contrary to expectations, CUD prevalence decreased significantly across all ages reporting daily/almost daily cannabis use between 2002–2016,” the study reports. Broken down by age groups, the prevalence of CUD among heavy pot users decreased by 26.8 percent in adolescents, by 29.7 percent in ages 18-25, and by 37.5 percent in those over 26.
"The findings contradict the predominating hypothesis that the prevalence of DSM-IV CUD would be stable, or increase, among those using with this regularity,” said Silvia Martins, MD, PhD, co-author of the study, in a statement. The study also found that the number of heavy pot users who admitted to driving while drunk or stoned decreased over the 14-year study period for all age groups.
Researchers theorized that changes in social attitudes towards cannabis might explain this unexpected reduction in problematic cannabis use.
"There could be several reasons behind these declining rates," Martins said. "First, the new national cannabis policy environment, with 33 states legalizing medical use and 10 states allowing recreational use of cannabis may have played a role in reducing stigma and perceptions of risk associated with cannabis use.”
“Secondly, increasing legalization may also be associated with changes in social attitudes resulting in fewer conflicts with relatives and friends around cannabis use."
Scientists have been unable to identify why some people end up experiencing symptoms of CUD, while the majority of cannabis users do not. One recent study has suggested that some individuals may be genetically predisposed to CUD, but further research will need to be conducted before this phenomenon can be fully understood.