Exploring the association between cannabis and opioid use among adults in Washington State: Estimates from a Cross-Sectional Survey

ABSTRACT Introduction Cannabis and opioids are commonly used for pain management. However, studies examining the association between use of both substances conflict. Furthermore, disruptions to healthcare services and access due to COVID-19 may have affected opioid use in favor of cannabis because of accessibility. Our objective was to examine associations between cannabis and opioid use in Washington State (WA), COVID-19’s impact on these associations, and the association between frequency of cannabis use and misuse of opioids. Methods We pooled cross-sectional data from 2019 and 2021 WA Behavior Risk Factors Surveillance Systems surveys to examine associations between cannabis use in the past 30 days and prescription or non-prescription opioid use and misuse during the past 12 months among adults 18 and older. Survey-weighted adjusted prevalence ratios were estimated using multivariable Poisson regression. A proportion test and adjusted trend test were used to examine trends between cannabis use frequency (no use, 1-5 days, 6-9 days, 10-29 days, and 30 days) and opioid misuse among those reported opioid use. Results Among 25,540 participants, the prevalence of opioid use was 19.2% among those who used cannabis and 13.8% among those who did not use cannabis (aPR=1.32; 95%CI: 1.20,1.46). COVID-19 did not modify the association between cannabis and opioid use. Among those who used opioids (n=2,168), daily cannabis use was associated with higher opioid misuse prevalence (aPR=2.64; 95% CI: 1.71,4.10), though less than daily use was not. Conclusion Cannabis and opioid use were positively associated. Our findings emphasize the need for cautious policy decisions on cannabis regulations. Promoting cannabis use may not correlate with a reduction in other substance misuse. Further research is warranted to explore patterns of cannabis and opioid misuse.