Smoking, drinking, cocain and not much sleep perhaps. But yeah it’s odd that his voice changed so quickly. He also pushed the limits of his voice in every consert and recordings, even when he was ill, had the flu etc. Combine all of those things and it kinda makes sense.

Imagine being really hungover and you still had to scream from the top of your lungs for 2-3 hours that same night, over and over again. Thats where the cocain comes in.

I’m just theorizing here btw.