Here's a question, if you're on a medication that can be deadly if overdosed, and you get to the point that you absolutely don't believe you would be able to survive a day without the meds, how is this any different than having a Cocaine or Heroin addiction?
Ok, I said that wrong, what I meant was psychological drugs, not ones that literally keep you alive, but ones that the body can survive without yet pyschologically make you feel dependant.
Either way, what happens if you find yourself in a situation where you don't have access to your drugs (stranded on a deserted island after a plane crash for exampe). I've asked this question on WP, so just to clarify, don't bother answering with "I don't fly" or "my country has better health care than yours so I have nothing to worry about" because this is strictly hypothetical.