I'm with Dr. Bromley. There are a variety of things that are addictive, and marijuana is probably one of them. Addiction is an interaction between a substance and a person. Some people are addicted to a variety of things, and that's a very complex story.
As far as clinical use goes, I'm entirely in agreement that we know precious little about it. We don't prescribe marijuana. We give them permission to use it with a “get out of jail free” card that we sign. This keeps them from getting busted unless they fail to adhere to certain rules about how much they can have and what they can have with it. My clinical choice is to use the commercially available preparations first.
The other challenge is that smoking itself is bad for you. I don't care what you're smoking—oregano, marijuana, or tobacco—smoking is bad for you. We also know precious little about the different strains. I have a patient who comes in with a book on different genetic strains of marijuana. He knows more about marijuana and genetics than I do about people. So it is a very difficult medical situation.