Two Years in: Legal Marijuana and Public Health in Colorado

BACKGROUND: After the legalization of recreational marijuana, the Retail Marijuana Health Monitoring Program at the Colorado Department of Public Health and Environment was given statutory responsibility to “Monitor changes in drug use patterns, broken down by county and race and ethnicity, and the emerging science and medical information relevant to the health effects associated with marijuana use.” With limited resources, the goal of this program was to utilize existing data sources to develop a broad picture of marijuana use and health impacts in post legalization Colorado.

METHODS: To monitor potential health outcomes associated with marijuana use, marijuana indicators were developed for existing data sources like the Colorado Hospital Association’s (CHA) discharge data and the Rocky Mountain Poison and Drug Center’s (RMPDC) data. In 2014, marijuana use indicators were added to the state questions of the Behavior Risk Factor Surveillance System, Colorado Child Health Survey (CHS), Influential Factors in Healthy Living (IFHL) survey, and the Pregnancy Risk Assessment Monitoring System (PRAMS) to monitor changes in marijuana use patterns in Colorado. Results from these surveys were augmented with results from existing marijuana use questions on the National Survey of Drug Use and Health (NSDUH) and the Healthy Kids Colorado Survey (HKCS). Analyses of these indicators were first published in a report in 2015 and are being updated as new data become available.

RESULTS: CHA discharge data show increasing trends in the rates of hospitalizations and emergency department visits associated with possible marijuana ICD-9 codes since legalization. RMPDC data reflect these same trends. Data from BRFSS did not show a significant increase in current marijuana use among adults 18 years or older (13.6%) when compared to the National Survey on Drug Use and Health (12.9%). There are conflicting data on adolescent marijuana use in Colorado compared to national averages with NSDUH results (2013) suggesting current use is higher than the national average and HKCS results (2013) suggesting it is lower than the national average.

CONCLUSIONS: While any conclusion regarding the impacts of legal marijuana is premature, available marijuana use data does not suggest substantial short term increases in current marijuana use among Colorado youth and adults. Discharge data and poison center calls show clear increasing trends related to marijuana, though the increases may be explained in part by the change in legal status. Continued surveillance is needed to draw any firm conclusions regarding the effects of legalization on marijuana use and health impacts.