Medical and Recreational Cannabis Laws Contributed to Increase in CUD Rates

Medical and recreational cannabis laws played a significant role in the rise in cannabis use disorder (CUD). These results were published in JAMA Psychiatry.

Data for this study were sourced from the US Veterans Health Administration (VHA) Corporate Data Warehouse. Between 2005 and 2019, veterans (N=3,234,382-4,579,994) who had contact with the VHA in a given year were included in this analysis. For each year, the rates of CUD were evaluated on the basis of passage of cannabis laws, in which 17 states had no cannabis laws, 22 states had only medical cannabis laws, and 11 states and Washington DC had medical and/or recreational cannabis laws.

In 2005, 5.7%, 61.6%, and 32.7% of the cohort were aged 18 to 34, 35 to 64, and 65 to 75 years; 75.0% were White, and 94.1% were men. In 2019, the proportions of age groups had shifted to 10.5%, 48.8%, and 40.7%, respectively, and 66.6% were White and 89.0% were men.

In general, there was a trend for CUD diagnoses to increase over time, in which the increasing trend was more prevalent in states with cannabis laws than states without laws. For example, in states without cannabis laws, the prevalence increased from 1.38% to 2.25%, in states with only medical cannabis laws CUD increased from 1.38% to 2.54%, and in states with medical and/or recreational cannabis laws from 1.40% to 2.56% in 2005 to 2019, respectively.

These rates indicated the absolute increase in CUD was 0.88% in states with no laws, 1.16% for states with medical laws, and 1.17% for states with medical and/or recreational laws. Stratified by age group, the greatest increase in CUD was observed among individuals aged 18 to 34 years (absolute change, 3.10% vs 3.11% vs 3.44%), followed by 35 to 64 years (absolute change, 1.57% vs 1.99% vs 1.86%) and 65 to 75 years (absolute change, 0.59% vs 0.75% vs 0.79%) for states with no, medical, and medical/recreational cannabis laws, respectively.

Overall, medical cannabis laws were associated with a 4.7% (P <.001) increase in absolute CUD rates compared with no laws and recreational and medical laws with a 9.8% (P <.001) increase compared with medical cannabis laws.

Stratified by state and the most recent law passage, the greatest increase in CUD rates was observed in Washington DC after the law passed in 2015.

These trends were not meaningfully affected when 1-year postenactment lags were implemented into models.

The results of this study may not be generalizable to a nonveteran population.

Study authors concluded, “The [United States] national increase in CUD diagnoses regardless of state laws underscores a growing need in the VHA and elsewhere to screen for cannabis use and offer evidence-based treatments for CUD. […] To inform future health and policy efforts, researchers must monitor harms related to increasing CUD, identify whether subgroups show particular risk due to changing cannabis laws, and ensure that this knowledge is clearly communicated to policy makers, clinicians, and the public.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.