Everybody has Cannabinoid Receptors in their body and the use of Medical Cannabis allows these receptors to fire faster while blocking other receptors that cause the body to feel pain (it's all in the brain). It's either that or it's the opposite - Cannabinoid Receptors are blocked - can't remember for sure. I did quite a bit of research on this when I was in College. I did a paper on it which included the way it works, the Nixon Report of 72', the War on Drugs, Cannabis being classified as a Schedule I Narcotic on the DEA Schedule (which we all know is B.S.) and many other areas.

Cannabis has been proven to help certain diseases and ailments which is why there are 13 states that allow the use of Medical Cannabis while there are others that are in the process of decriminalizing it. It's my belief that it will never become legal since that would make several of our past and present Presidents seem like they had no idea what they were talking about when it came to this issue (though we all know they had no idea - but everyone needs to realize that the Presidents weren't the ones doing the research - it was their "people" who provided them with misinformation). Case in point - the Nixon Report which was conducted by a team of scientists at the New York Academy of Science and it was found that Cannabis had no side effects, no addiction characteristics, among other positive results of their findings. Nixon decided that he was going to have the report changed to reflect all negative affects. Bear in mind - this was Nixon who couldn't be believed on anything - he could be holding a rock in his hand, tell you it was a rock, let you touch it, hold it, and it probably wouldn't have been a rock.