I like this piece of research because it correlates with what I believe about superficial therapies such as CBT and those that tout positive thinking and positive affirmation as the way out of depression. I do think that CBT and NLP have uses for specific behaviours but they won't affect the core beliefs of a person. Worse, positive affirmation may make a person feel worse, according to this research, if what they are trying to instill in themselves contradicts what they actually believe about themselves.

things they do because of underlying, fundamental (and often subconscious) core beliefs such as "I am worthless", "I am not worthy of love" "my needs are not important" and "I only deserve bad things to happen me" (not exhaustive by any means!). These are what leads to depression, not the thought processes that are symptomatic of these core beliefs. I believe that potent counselling will address the underlying causes through the therapeutic relationship.
I also think this piece of research is highly flawed. Basically, whatever you believe, you can find some research to back it up!