Of the articles I have read on Stephen Paddock, the general consensus seems to be that he was not mentally ill. I think that he was psychotic, as he obviously believed he was morally and ethically entitled to kill and injure all those people.
Some don’t feel that his father’s criminal behavior had anything to do with his mental health. But I think the experts should do a few studies on children who had a parent incarcerated when they were a young age. How does that affect their mental health years later? Society took his father away at a time when he was influenced. Socially and mentally, he needed his father. He probably felt justified to repay society for this “unjustification,” even though it was his father who did wrong.
Also, gambling can be addictive and bring about depression. It’s a good feeling when you are winning but a bad feeling when you are on a losing streak.
I feel there’s a fine line between mentally ill and “normal.” I feel he wanted to commit suicide and to take as many as he could out with him.