This is actually scientifically true, not just because of tolerance, but because of the effect of opiates on the pain beast itself. When someone with true physical pain takes a narcotic painkiller, the majority of that drug goes straight to the pain receptors in the brain, whereas if you are just looking to get high, the drug sort of floats around the brain and actually does just that. It is a double edged sword, however, because over the long term, opiates suppress the body's ability to produce endorphins, the natural substances that reduce pain in our bodies. This is why we often have tremendous 'rebound' pain when we go off of opiates after long term use. It's also a fact that the incidnce of actual addiction is much lower in true pain patients than it is in recreational users. For me personally, after being on everything from morphine to hydro in the past year, the worst W/D's I have ever had were just the tremendous increase in the original pain for which I was prescribed the drugs for in the first place. Of course, YMMV...