The role of cannabis reform in shaping North America’s overdose and addiction crisis remains hotly contested. People who inject drugs (PWID) sometimes substitute cannabis for opioids. Yet, no research has examined the effects of cannabis legalization on opioid use among PWID– despite major potential for PWID to benefit from policy interventions reducing opioid-related harms. We examined whether legalizing cannabis for medical use (MCL) vs. both MCL and adult/recreational use (MCL+RCL) was associated with changes in substance use among PWID, overall and by sex and race/ethnicity.
