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Legal marijuana use linked to more dependency, persistent vomiting

Chronic use of cannabinoid derivatives led to a significant increase in cannabinoid hyperemesis syndrome, characterized by episodes of severe nausea and cyclical vomiting, the symptoms of which improve with cannabis cessation, as well as cannabinoid dependency.

“Although recent liberalization of cannabis will likely have major impacts on health care, there have been no studies on health care utilization since year 2009 when federal Department of Justice office acted favorably toward medical marijuana use,” Mustafa Al-Shammari, MD, from the department of internal medicine, University of Nevada, Las Vegas School of Medicine, and colleagues wrote. “There are growing concerns about legalizing of marijuana use and its related public health effects.”

To investigate the association between cannabinoid use and hospitalization, Al-Shammari and colleagues reviewed patient discharge data from the Healthcare Utilization Project National Inpatient Sample.

The study assessments comprised three periods: pre-legalization of marijuana (January 1993 to December 2008); the legalization period (January to December 2009); and the post-legalization period (January 2010 to December 2014).

In all three periods, there was an increase in use of the diagnosis code for cannabinoid dependency unspecified, from pre-legalization (international rate ratio = 1.046; 95% CI, 1.036-1.056), to the legalization period (IRR = 1.179; 95% CI, 1.027-1.353), through post-legalization (IRR = 1.058; 95% CI, 1.02-1.097). The ratios represent a mean growth rate of approximately 6% after policy implementation compared with the pre-legalization period.

Regarding persistent vomiting, also classified by its diagnosis code, rates only increased significantly in the post-legalization period (IRR = 1.084; 95% CI, 1.043-1.276), representing a growth rate of approximately 8% after policy implementation. However, aggregated cannabinoid dependency unspecified and persistent vomiting rates showed significant increase from the pre-legalization period (IRR = 1.02; 95% CI, 1.012-1.027), to the legalization period in 2009 (IRR = 1.164; 95% CI, 1.032-1.312), through the post-legalization period (IRR = 1.077; 95% CI, 1.043-1.112).

“Adult cannabis users in [recently surveyed] states reported more cannabis use in the past 30 days, more daily use and more cannabis-related problems than cannabis users in states not allowing medical marijuana use,” the researchers wrote. “Heavier cannabis use is very likely to increase the prevalence of cannabis dependency. Although [the] legalization process has developed rapidly in the past decade, the state level regulatory efforts have been behind.”

From 1993 to 2008, cannabinoid dependency unspecified diagnosis showed an average growth rate of 4.63% among patients, which accelerated in 2009 during legalization and reached an average growth rate of 10.46% per year between 2009 and 2014. Persistent vomiting rates did not increase significantly prior to 2008 or through 2009, but did increase after marijuana legalization at an average growth rate of 9.12% per year from 2009 to 2014.

After the researchers aggregated the cannabinoid dependency unspecified and persistent vomiting growth rates, they found an average growth rate of 2.01% between 1993 and 2008, which increased to 10.46% per year from 2009 to 2014.

“The influences of recreational marijuana legalization process possibly accommodating public opinions on public health are still unknown,” the researchers concluded. “Future rigorous health outcome evaluation is urgently needed to measure cannabis-related harm in states [with] legalized recreational use. Further public health policies such as higher rates of taxation and restrictions on public advertisement might be warranted to protect health of adults with polysubstance dependency and adolescents. These policies should be implemented before a profitable marijuana industry grows and governs local or national market to resist these public health policies legislation.” – by Talitha Bennett

Disclosure: The researchers report no relevant financial disclosures.