A study conducted by University of Oxford researchers indicates that cannabis -- specifically THC -- works as a pain reliever in some people not by reducing the pain, but by distracting the user from the pain, reports the University of Oxford:
"We have revealed new information about the neural basis of cannabis-induced pain relief," says lead researcher Dr Michael Lee of Oxford University's Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB). "Cannabis does not seem to act like a conventional pain medicine. Some people respond really well, others not at all, or even poorly. Brain imaging shows little reduction in the brain regions that code for the sensation of pain, which is what we tend to see with drugs like opiates. Instead cannabis appears to mainly affect the emotional reaction to pain in a highly variable way."
Also, only half the study participants felt any change in pain, indicating that THC's impacts vary widely among individuals. Lee says the small-scale study is but a piece of the puzzle of how cannabis interacts with pain, and there's much more to be learned.