As depressing as it sounds, my mom thinks he committed suicide.She explained it this way. He was nearly $500mil in debt, and his upcoming tour would only get him $54mil. There's no way he'd be able to pay that kind of debt off.
Here's the interesting part. His four-hour physical for his tour came back with the results of "no problems whatsoever". So it brings the question, why does he have so much medication? My mom thinks he paid off the doctor to say there were no medical problems, but he knew he wouldn't be able to do it. He also had a lawsuit filed against him by a Beverly Hills Pharmacy for owing over $100,000 in prescriptions in a two-year period.
It sounds morbid, but it makes sense :/
I'm curious to see how his autopsy goes. I really want to know the toxicology reports. I honestly hope it wasn't a suicide, but by the way it sounds, it almost seems to point in that direction.