Contrary to some claims, people in the U.S may not be substituting cannabis for opioids, according to new research at Columbia University Mailman School of Public Health. The study examined the direction and strength of association between cannabis and opioid use over 90 consecutive days among adults who used non-medical opioids.
The findings showed that opioid use was at least as prevalent on days when cannabis was used as on days when it was not, and that this was irrespective whether participants were experiencing pain or not. The study, published in the scientific journal Addiction, is among the first to test opioid substitution directly.
The study, which compared the probability of non-medical opioid use on days when cannabis was used with days when cannabis was not used, included 13,271 days of observation among 211 participants from the greater New York area. The participants were predominantly male, urban, unemployed, unmarried, and had a high prevalence of substance misuse and pain.
“Our results suggest that cannabis seldom serves as a substitute for non-medical opioids among opioid-using adults, even among those who report experiencing moderate or more severe pain,” said Deborah Hasin, professor of epidemiology at Columbia Mailman School and a professor in the Department of Psychiatry at Columbia University Irving Medical Center. “In other words, our study suggests that cannabis is not an effective way to limit non-medical opioid use.”
In 2017, there were over 2 million people with opioid use disorder and over 70,000 opioid-related deaths in the US. Illicit opioid use, including non-medical use of prescription opioids, synthetic opioids and heroin, are the primary cause of overdose deaths among U.S. adults.
Understanding how cannabis may change non-medical opioid use is critical to informing discussions around cannabis-based interventions for addressing the opioid crisis.
Background and Aims
Ecological studies have suggested that Cannabis legalization might have led to a decrease in opioid overdose deaths. Such studies do not provide information about whether individuals are substituting Cannabis for opioids at different points in time. The current study assessed the magnitude of the daily association between Cannabis and opioid use in individual adults with and without pain who use non‐medical opioids.
Prospective cohort study.
The greater New York area and a suburban inpatient addiction program.
Adults with problem substance use who use non‐medical opioids, recruited from May 2016–June 2019. The analytical sample included 13 271 days of observation among 211 participants (64% male, 41% white, 78% unmarried, 80% unemployed, mean age 43 years).
Participants completed interviewer‐ and self‐administered computerized surveys, and then responded to an interactive voice response (IVR) system daily for the following 90 days. The main exposures, Cannabis use and pain, were defined as responding affirmatively to the IVR question: ‘Did you use Cannabis yesterday?’ and endorsing moderate or severe pain at baseline, respectively. The main outcome, non‐medical or illicit opioid use during 90‐day follow‐up, was defined as responding affirmatively to IVR question: ‘Did you use heroin yesterday?’ or ‘Did you use prescription opioids more than prescribed or without a prescription yesterday?’.
The mean IVR completion rate was 70%. The unadjusted odds ratio (aOR) indicating same‐day use of Cannabis and opioids was 2.00 [95% confidence interval (CI) = 1.54–2.59]. Controlling for demographic characteristics, recruitment method, opioid types at baseline and pain, the aOR was 1.86 (95% CI = 1.44–2.41). A test of interaction between pain and Cannabis use to determine if the association of Cannabis with opioid use differed between people with moderate‐to‐severe pain and less‐than‐moderate pain was inconclusive.
Among US adults with problem substance use who use non‐medical opioids, the odds of opioid use appear to be approximately doubled on days when Cannabis is used. This relationship does not appear to differ between people with moderate or more severe pain versus less than moderate pain, suggesting that Cannabis is not being used as a substitute for illegal opioids.