Mental illness? You obviously don't understand that a change in one's perception of what they feel about the world can make significant changes of what exactly happens in their. Just look at the placebo effect and how it’s been scientifically proven to radically change one’s state and health even more so than a drug, just because of a change in their thinking.
Have you ever considered why some people from wealthy and rich families, become poor, and why there are some people who have nothing, like people that come to Australia and are able to build a successful life and legacy for their family and their generations? I have a friend, who fought in WW2 and had no education, came here when he was 50, but was still able to build a business that pays a large amount of residual income whether he works or not. Why? Because, he didn't want to be a fucking outcast and have self-pity on himself. He could have sat around and cried and did nothing about his situtation. But no, he knew he was better then that.
We live in the same world, we have the same 24hrs, and guess what? Shit will always happen to everyone, regardless of how skillful you are. You’re responsible for what happens in your LIFE. Everything happens in your life is created through either your own mental or physical actions. If you want to be poor, then go spend or your money today, have shitty eating habits, and go do drugs and alcohol. If one decides to go on to a life like that, do you think that someone forced them to do it?
People fail at life, is because they impose self-liminations on themselves and let any reason distract them from getting better, whether it be the economy, competition or other people dictating how they should feel and how should act.