Many patients suffering from post-traumatic stress problems who learned the TM technique showed significant reduction in depression after four months, in contrast to others who were randomly assigned to receive psychotherapy. Reference: Journal of Counseling and Development 64:212-215, 1985.
Additional research studies on depression:
Elder C, Nidich S, Colbert R, Hagelin J, Grayshield L, Oviedo-Lim D, Nidich R, Rainforth M, Jones C, Gerace D. Reduced psychological distress in racial and ethnic minority students practicing the Transcendental Meditation Program. Journal of Instructional Psychology 2011 38(2):109-116
Elder C, Nidich S, Moriarty F, Nidich R. Effect of Transcendental Meditation on employee stress, depression, and burnout: a randomized controlled study. The Permanente Journal 2014 18(1):19-23.
Ferguson P.C., et al. Psychological Findings on Transcendental Meditation. Journal of Humanistic Psychology 16:483-488, 1976.