Chris took a lot of hits to the head. Both unprotected punches, chairs, going through tables etc. And him using the diving headbutt and doing it unprotected didn't help. His brain was basically mashed potatoes at the end and as was pointed out earlier in this thread by Jacob, comparable to a 80+ year old man with Alzheimer.I can't remember whether it was pain pills or what. but they say his brain was "ate up" I remember. Then he laid Bibles down where his family was and after killing them killed himself. The last few years of his life I know nothing about. Someone who would do this couldn't be right.
Combine that with pill, drink and steroid problems (all of this has been pointed out about him by friends of his. Chris was not doing well at the end and drank a lot to deal with the pain) and it was almost the perfect storm for something like this sadly.
The Chris that killed his family was not the real Chris most likely. But it was still a heinous act and should be a warning sign to any wrestler that doesn't worry about what type of bumps they take and what they put in themselves/how much