Colorado publishes report on cannabis use trends

Following the legalisation of recreational cannabis in the US state of Colorado at the end of 2012, the state Senate mandated a report every two years on changes in cannabis use patterns, relevant scientific evidence and adverse health events. The second such report was presented to the Colorado state bodies on 30 January 2017. Some trends cover legalisation of medical cannabis from 2000, and its commercialisation from 2009 (see report for details).

This 300-page report is comprehensive, yet easy to read. Section 1 on changing use patterns contains analyses of five surveys of different populations (adults, adolescents etc.), and highlights ‘major findings’ for each. Section 2 outlines the results of a review of the scientific literature on relevant topics such as cancer, cardiovascular effects, driving, mental health effects, reproductive effects and unintentional exposures in children. It summarises evidence for each topic as substantial, moderate, limited, mixed or insufficient; it also provides clear ‘Public health statements’ and ‘Public health recommendations’. Section 3 contains analyses of data from the poison and drug centre and visits to hospitals in Colorado, again highlighting ‘major findings’ for each analysis.

Findings specific to Colorado included:

  • According to two different surveys, 13 % or 17 % of adults used cannabis in the last month in 2015 (the highest national rate in the EU is 7 %, in France). This rose to 26 % of those aged 18–25. Last-month use has been rising since 2006. An estimated 6 % of adults in Colorado used cannabis daily (the highest national rate in the EU is 3 %, in Spain).
  • About 38 % of students aged 14-18 have ever used cannabis (the highest national rate in the EU is 37 %, among 15- to 16-year-old students in Czech Republic), with nearly all usually smoking (87 %), rather than vaporising (5 %) or ingesting (2 %). In Colorado, rates of use in this age group fluctuate from 2005 to 2015. The rate of last month use is nearly identical to the US national average.
  • There were 1688 ‘human cannabis exposure’ phone calls to the Rocky Mountain Poison and Drug Center (RMPDC) between 2000 and 2016. Call volume significantly increased following commercialisation of medical cannabis in 2009, then further following the legalisation of commercial recreational cannabis in 2014. The number of calls decreased slightly in 2016.
  • There were 529 cannabis-related calls to the RMPDC between July 2014 and December 2016. Of these, 203 related to edible products and 199 to smokeable products. Regarding children aged 0–8, 60 calls related to edible products and 28 to smokeable products.
  • From 2000 until September 2015, there were increasing trends in the rates of cannabis-related hospital visits and emergency department visits. The rate of hospital visits continued to climb in 2015, but the rate of emergency department visits fell slightly compared to 2014.

Link to report: