Matthieu Ricard: Meditate yourself better - opinion - 03 February 2010 - New Scientist
(Despite the name, New Scientist is a mainstream magazine for scientists and laymen alike, not particularly New Age. So when they let statements like this stand on their own, you can assume it is already accepted as fact in the scientific community.)
"20 minutes of daily practice can contribute significantly to a reduction of anxiety and stress, the tendency to become angry and the risk of relapse in cases of severe depression. Thirty minutes a day over the course of eight weeks results in a considerable strengthening of the immune system and of one's capacity for concentration. It also speeds up the healing of psoriasis and decreases arterial tension in people suffering from hypertension."