Learning From Past Mistakes – Opioids, Cannabis and the Treatment of Chronic Non-Cancer Pain Conditions

Background. Finding effective treatments for chronic pain is a major public health challenge. In the 1980s and 1990s, claims of opioid effectiveness without addiction for Chronic Non-Cancer Pain (CNCP) conditions were rooted in uncritical citation of faulty science by the pharmaceutical industry and physicians. The national public heath impact of the ‘opioid epidemic’ is well known. In the 2000s, Medical Cannabis has proliferated as a physician-prescribed treatment for CNCP conditions in the face of uncertain evidence. Some are questioning: has the medical community ‘repeated past mistakes’ in chronic pain management? We approach this question with a comparative analysis of quality of evidence for opioids and cannabis for CNCP conditions during their periods of liberalization. Method. We identified the ‘liberalization periods’ for Opioids as 1989-1999, and Medical Cannabis as 1998–2008 and conducted a literature search for Randomized Control Trials (RCTs) in these time periods. We then conducted modified GRADE criteria evaluations (Cochrane Collaborative tool for assessing Quality of Evidence) for each body of evidence, and contextualized our findings. Results. Opioids: Very Low quality evidence; concerns regarding publication bias, handling of dropouts and outcome data, vague method descriptions and indirectness of population and intervention. Cannabis: Low - Very Low quality evidence; concerns regarding publication bias, potential issues with blinding and indirectness of population. Conclusions & Discussion. It is important to consider several factors, including differences in scientific rigor in each time period and DEA schedule I classification of marijuana being a barrier to conducting studies. Still, there is a striking parallel of prescribing practices outpacing evidence quality. Policy Implications. Rescheduling Marijuana from Schedule I, reinforcing quality and rigor standards for clinical trials, and better integration of evidence interpretation and synthesis into medical school curricula are all warranted