The chapter of Foley is Good on drug use in the WWE makes an interesting case for the personal responsibility of a wrestler being where the buck stops as far as drug (ab)use is concerned, but I think Mick simplifies things a little. While it is definitely the decision of the wrestler at the end of the day, there are certainly a lot of pressures to perform and be able to stay in the business that aren't addressed. I would consider Mick a special case because of his unusually high pain tolerance and good fortune within his career, whereas the average wrester I would imagine has to deal with great amounts of pain. Contemporary wrestling has done a lot to prevent unnecessary injury or pain, but when one is relying on the performance of their body for their livelihood, it seems to me that anything to keep it in good working order would be appealing. I wouldn't try and point the finger at Vince McMahon as pushing anything on anyone, but the pressure and expectation to perform doesn't have to be articulated.
I was also surprised to see discussions on sleeplessness, depression, and anxiety, but after watching The Mania Behind Wrestlemania it makes a lot of sense. It's easy to forget that wrestlers have personal lives and have to continually juggle their families, their jobs, and their celebrity.
I agree that drugs are a problem for society in general, though it seems that wrestlers have inordinate need and access to them and that's a shame. I can only hope that drug use has dwindled in the years since the writing of the book (excluding RVD), and I would like to think that these days wrestlers don't necessarily need pain pills. Though I enjoy seeing wrestlers beat each other up, I fervently hope that it doesn't hurt them. Sacrificing your body for the enjoyment of the masses is noble in a way, but old age seems hard enough without ruining all the cartilage in your joints.