Let's be clear: if people are having a hard time trying to quit a drug, with physical symptoms, and they often fail, then it is addictive. Ignore what the doctors say while trying to cover their ass and look at the physical evidence.
Drug addiction charities need to be more helpful for people with clinical drug addictions, because street drugs aren't the whole problem. It doesn't magically stop being a problem just because their pusher wore a white coat.
If you have a problem with a substance, and you can't get clinical help because nobody believes it is a real problem, stop trying to wring blood out of a stone. Go to the peer support groups. They damn well know what it's like to have a monkey on your back, and can help you deal with it. There are religious and secular programs, most of them free, so take your pick.