I think self sabotage and fear of success and happiness are real phenomenons. I don't see how they relate to real depression and anxiety. In my experience they come from low self worth. When in a depression I may have those types of symptoms but they come from being in the depression not from my attitude toward life and success.

As TJ said because I have lived with depression my whole life I have had to accept limitations and not shoot for the moon. That is reality not self sabotage. I don't give the study much credence. Of course changing your attitude about many things can help you in general but in my experience will not cure my depression. Depression is a very organic physical thing for me and happy positive thoughts do not put a dent in it.