Population-level analyses cannot tell us anything about individual-level marijuana-opioid substitution patterns

Abstract

Livingston et al.1 studied the state-level correlation between opioid overdose deaths and recreational marijuana legislation. In the article’s introduction, the authors claim that the study will contribute to the literature on “whether cannabis is substituted for opioids in pain management,” and the reader is given the premise that “with this substitution, an immediate reduction in opioid-related poisonings would be expected.” Therefore, those who read the study’s findings—that recreational marijuana legislation was followed by 0.7 fewer opioid overdose deaths statewide per month—are led to believe that the study constitutes evidence that pain-afflicted individuals in Colorado are substituting marijuana for opioids.