46% of cannabis users reported replacing their prescription medications — mostly opioids, anxiety meds, and antidepressants

Of 2,774 cannabis users surveyed, 1,248 (46%) reported using cannabis as a substitute for prescription drugs. The most commonly replaced drug classes were opioids/narcotics (35.8%), anxiolytics/benzodiazepines (13.6%), and antidepressants (12.7%). A total of 2,473 substitutions were reported — approximately two medications per person who substituted. Medical cannabis users were 4.59 times more likely to substitute (95% CI 3.87-5.43). Female medical users showed the strongest signal at OR 6.09 (95% CI 4.65-7.80). State legal status had no significant effect on substitution behavior (47% vs 45%, p=0.58).

Anonymous online 44-item questionnaire using REDCap, with PROMIS Global Health 10-item short form. Self-selected convenience sample of 2,774 cannabis users who had used at least once in the past 90 days. Recruited through social media, cannabis dispensary flyers in Washington State, Bastyr University website, public lectures, and online cannabis magazine. Data collected December 2013 to January 2016. Bastyr University IRB approved.

This study quantified a phenomenon that healthcare systems were largely ignoring: widespread, patient-driven substitution of cannabis for prescription medications. The finding that nearly half of cannabis users replace prescription drugs — particularly opioids during the peak of the opioid epidemic — has implications for harm reduction, clinical practice, and drug policy. The legal status finding is equally important: substitution happens regardless of the law, suggesting healthcare systems need to engage with this behavior rather than pretend it depends on policy.

Corroon's study is part of a convergent evidence base — from population-level mortality data (Bachhuber 2014) to prescribing records (Bradford 2016) to dispensary surveys (Boehnke 2016) to prospective cohorts (Lucas 2021) — all pointing in the same direction: when people have access to cannabis, many reduce their use of prescription medications. The question is no longer whether this happens, but whether it leads to better or worse health outcomes.

Self-selected convenience sample recruited through cannabis-friendly channels, likely overrepresenting cannabis enthusiasts. Self-reported substitution with no clinical verification of medication changes or outcomes. Open-ended drug names created coding challenges. Some substituted drugs may have been OTC rather than prescription. PROMIS health scores show the sample was significantly less healthy than the general population. Timeline mismatch between data collection period (2013-2016) and legal status analysis date (2016). No information on whether substitution was medically supervised.