Evidence on Medical Marijuana Safety and Effectiveness: Read with Caution

The Consortium leads for evidence and for MEMORY, Dr. Amie Goodin and Dr. Joshua Brown, published a commentary on the rigor of studies evaluating the safety and effectiveness of medical marijuana in the Consortium’s Evidence in Context Series: High Risk of Bias in Medical Cannabis and Cannabinoid Clinical Trials Dictates the Need for Cautious Interpretation.

Pyramid showing the risk of bias between different research including RCTs and meta-analyses — Clinical evidence pyramid showing increasing quality of evidence. RCT, randomized control trial.

RCTs are generally considered the “gold standard” of evidence and commonly inform clinical guidelines, lead to the approval of new drugs, and are often disseminated to the public through media coverage.

The use of meta-analyses serves to combine the evidence from multiple trials while providing an objective, systematic quality assessment of these studies. Several meta-analyses illustrate the low quality and poor rigor of studies that support the effectiveness of medical marijuana.

Readers of the primary literature need to be aware of the impact of problems in study design and analysis when interpreting the results.

Read the full commentary in Medical Cannabis and Cannabinoids.

This article is part of a commentary series called Evidence in Context. Read about the Evidence in Context series.