Hazy Memory Predicts Depression?

A recent study reviewed by the NY Times, entitled "Hazy Recall as a Signal Foretelling Depression" examines an individual's ability to recall a very specific versus generalized emotional memory. Researchers speculate that this overgeneral memory may contribute to mental health disorders later on, including depression and PTSD. What might be a confounding variable in these types of studies? How might researchers and psychologists use this information to help treat individuals with mental health problems?