Honestly, I don't think any "facts" do. I didn't choose to get MS or Fibromyalgia... but if I choose to "medicate" myself with illegal substances or alcohol to deal with the pain and fear, there is a HUGE difference there. Don't get me wrong... I honestly feel badly for everyone with a chemical dependency. But I did nothing to get the actual, honest-to-goodness diseases that I do have. It angers me that addiction is put on that same level.
The most addictive drugs are like opium as they are very similar molecules to you own endorphins (search google) secreted in you brain when you experience pleasure. You never forget the opiates (search google). I had it once in hospital. They can cause severe constipation as a side affect. Most drugs have side affects. I usually take none other then aspirin.