Some reports are coming out that Hunter S. Thompson hadn't recovered from a broken leg and hip, causing him great pain that reduced his mobility, kept him out of his favorite tavern, kept him from traveling, and causing him a lot of pain. The depression from being almost a phone-dependent shut-in combined with the pain may have been what convinced him to blow his brains out.
Take that as a lesson, kids. The more drugs you do now, the bigger the tolerance you'll build to them and the less effective they'll be when you really need them.