A recent study published in JAMA Psychiatry reveals that medical cannabis laws (MCLs) are linked to a significant increase in cannabis use disorder (CUD) and cannabis poisoning. Recreational cannabis laws (RCLs), on the other hand, are associated with an uptick in cannabis poisoning cases.

The research, led by Jayani Jayawardhana, Ph.D., from the College of Public Health at the University of Kentucky, analyzed the impact of state-level cannabis laws on public health outcomes. The longitudinal study spanned a decade, from January 2011 to December 2021, covering all 50 states and the District of Columbia. It assessed adults aged 18 to 64 years, examining trends in diagnoses of CUD and cannabis poisoning before and after the implementation of MCLs and RCLs.

The study, which included over 110 million enrollees, found that states implementing MCLs experienced a sharp rise in diagnoses: 31.09 additional cases of CUD and 0.76 cases of cannabis poisoning per 100,000 enrollees each quarter. In states with RCLs, there was a notable increase in cannabis poisoning diagnoses by 0.34 per 100,000 enrollees per quarter.

Interestingly, the study did not find significant associations between opening medical cannabis dispensaries or allowing home cultivation of medical cannabis and increased rates of CUD or poisoning. However, the data revealed demographic disparities. Female enrollees and individuals aged 35 to 44 years showed higher relative increases in CUD diagnoses compared to males and other age groups.

“These increases may burden health care systems, emphasizing the need to couple cannabis laws with effective policy interventions and treatments for patients experiencing adverse health effects of cannabis,” the authors noted.

The findings highlight the unintended consequences of cannabis legalization and underscore the need for comprehensive public health strategies to mitigate risks while balancing the benefits of medical and recreational cannabis use.