I completely get what you are saying and have had some psychology as well as an undergrad. You're right though people can go through tough times and it can happen to anyone. What I'm trying to say is that there must have been some incident that made you want to turn it around and that is what I'm trying to say someone needs. There has to come a certain time when you want to make the change and it sounds like you did. I have over come adversity through similar techniques and what I'm trying to say is that there isn't going to be some magical switch that will give motivation it is going to have to come from the inside that you want to make the change and get off your butt. Once you have made that decision then yes visualization and affirmation can push you that much higher, but that inital leap usually has to come from oneself and the pure want to succeed.
offcorse thats all true, ultimatley you have to fight for yourself and noone else, in thailand my trainer asked me before fighting if i did it for myself and not to prove anything, he even says so in this clip YouTube - A Lanna Trilogy - Getting Fights