An article from the latest issue of the APA Monitor says about depression,
Depression is not only the most common mental illness, it’s also one of the most tenacious. Up to 80 percent of people who experience a major depressive episode may relapse.
A recent study – one of a growing body of research as noted in the article – shows that one form of mindfulness training can be as effective as antidepressant medication in preventing a recurrence of depressive symptoms.
Here is a TED talk by Zindal Segal, PhD, one of the leading researchers in the area.