While records of medical and therapeutic use of cannabis go back thousands of years, several points in history proved instrumental to furthering the ongoing body of research. A key figure in this story was Dr. William Brooke O’Shaughnessy, who actively practiced medicine and worked as a researcher in the 1800s. While in India in the 1830s, he worked to validate area folk remedies that used cannabis, including its role in mitigating pain and spasticity, eventually bringing this knowledge back to England—and formal Western medicine.

Years later, Israeli scientist Raphael Mechoulam, Ph.D., professor at The Hebrew University of Jerusalem, first isolated tetrahydrocannabinol (THC) working in the university’s Center for Research on Pain in 1964. Israel was subsequently an early adopter of medical cannabis use in the 1990s.