Wider availability of medical marijuana in Colorado starting in 2009 coincided with an increase in calls to poison control centers and hospital discharges, according to a study published in the American Journal of Preventive Medicine.1
Researchers led by Jonathan M. Davis, PhD, from the University of Denver, found that the public health effects were significant — a 57% increase (95% CI, 43.4 – 72.0%, P < .001) in marijuana-coded hospital discharges from 2007 to 2013, and a 56% increase (95% CI, 49.0 – 62.8%, P < .001) in calls to poison control centers after 2009.
Colorado voters chose to legalize marijuana for recreational use in 2012, and the findings represent a cautionary tale for states that have voted or will be voting on this issue.
“In 2009 there was a big change. In that year, the Department of Justice instructed federal prosecutors not to focus on individuals who were in compliance with state marijuana laws. People no longer had to worry about getting in trouble with the [Drug Enforcement Administration],” Dr Davis told Clinical Pain Advisor.
A Change in Public Perception
Analysis of Colorado records showed that poison control calls for marijuana increased by 0.8% per month after 2009 (95% CI, 0.2 – 1.4%; P <.01, and hospital discharges coded as marijuana dependence increased 1% each month from 2007 to 2013 (95% CI, 0.8 – 1.1%, P < .001).
The monthly number of applications for medical marijuana increased more than 20-fold in 2009 alone, from 495 in January to over 10,000 by December. Significantly, there was 1 dependency-related hospital discharge for every 3.159 (95% CI, 2.465 – 3853; P < .001) medical marijuana applications.
Admissions for marijuana dependence treatment showed the opposite trend, decreasing by 0.7% (95% CI, 0.9 – 0.5%, P < .001) per month after 2009, accompanied by a 26% decrease in marijuana arrests (95% CI, 31.1 – 20.3%, P < .001).
“The decrease in treatment probably reflects the decrease in arrests [and] mandatory treatment sentencing. It was probably not a personal choice to avoid treatment,” Dr Davis explained.
“When taken with changes suggesting a decrease in the perceived risk of marijuana, these factors may mark increased use and increased acceptance of marijuana,” the authors noted.