The researchers found that an oral tablet of THC, the psychoactive ingredient in cannabis, tended to make the experience of pain more bearable, rather than actually reduce the intensity of the pain. MRI brain imaging showed reduced activity in key areas of the brain that substantiated the pain relief the study participants experienced. 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, he says. 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. - University of Oxford
