Abstract

Nearly 10% of cannabis users in the United States report using it for medicinal purposes. As of August 2019, 33 states and the District of Columbia have initiated policies allowing the use of cannabis or cannabinoids for the management of specific medical conditions. Yet, the federal government still classifies cannabis as illegal, complicating its medical use and research into its effectiveness as a treatment for the various conditions purported to benefit from cannabis pharmacotherapy. Because of this conflict and restrictions on cannabis research, evidence of the efficacy of cannabis to manage various diseases is often lacking. This article updates a review published in the June 23, 2015, issue of JAMA and describes newer evidence regarding what is known and not known about the efficacy of cannabis and cannabinoids for managing various conditions.