The difference between say prozac helping your fibromyalgia and vicodin is that vicodin has been proven to be physically and mentally addicting while prozac doesn't really have that much of a threat. When using medications long term, you have to search for a medication that isn't potentionally going to be abused. I believe that's why there's a big difference in narcotics and antidepressents. That's just my take on it, though.