U.S. researchers said Wednesday they have reproduced the pain-relieving effects of cannabis with a synthesized compound that avoids the mind-altering, addictive qualities of the natural plant.

For centuries, people have used marijuana to treat pain, but its psychoactive effects (such as mood changes and cognitive impairment) make it unsuitable as a mainstream medical treatment. Researchers set out to create a cannabis-based drug that provides pain relief without altering mood or causing addiction.