Michael A. Diefenbach, PhD

Professor, Center for Health Innovations and Outcomes Research (CHIOR), The Feinstein Institute for Medical Research

Director, Behavioral Research, Department of Medicine & Urology

Professor, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell

Phone: (516) 321-8001
Email: mdiefenbach@northwell.edu

About the Investigator

Dr. Diefenbach is a behavioral scientist with a degree in Health/Social Psychology whose research focuses on how patients make treatment decisions under distressing and uncertain medical conditions. He has investigated basic psychological mechanisms of decision making, focusing on individual cognitive and affective factors and their influences on information processing, decisional satisfaction, regret and quality of life. Guided by a self-regulation theoretical framework, Dr. Diefenbach translates and applies basic psychological phenomena into applied patient focused interventions with the goal of enhancing patient quality of life through improved decision making and symptom control.

Dr. Diefenbach’s research has been continuously federally funded for over 20 years and has involved a variety of patient populations, including prostate, bladder, and breast cancer patients. In an effort to enhance patient decision making he has developed in-person as well as web-based programs. His Prostate-Interactive Education System (PIES) was one of the first web-based comprehensive and interactive prostate cancer information resources for newly diagnosed prostate cancer patients. In addition, he guided the development of three additional programs: Healing Choices for Prostate Cancer and Healing Choices for Breast Cancer, as well as a web-based resource for prostate cancer survivors (PROGRESS).

More recently, Dr. Diefenbach developed applications for the smart phone to support a slow-breathing exercise to control vasomotor symptoms experienced by men on androgen deprivation therapy (2Breathe) and a cancer screening information tool (HealthOwl). He is currently developing a decision making application for a low-health literate prostate cancer population (Healium).

Before joining Northwell Health, Dr. Diefenbach was Associate Professor of Urology and Oncological Sciences at the Icahn School of Medicine at Mount Sinai, New York. Dr. Diefenbach serves on the editorial board of Annals of Behavioral Medicine and Cancer Epidemiology, Biomarkers, and Prevention. He is also a Senior Editor of Translational Behavioral Medicine. He is a frequent reviewer for the Department of Defense, the Veteran’s Administration and the National Institutes of Health, where he served as a permanent member of the Behavioral Medicine and Intervention study section (BMIO). He was elected to Fellow status of the Society of Behavioral Medicine and the Academy of Behavioral Medicine. He has been serving as secretary/treasurer of the Society of Behavioral Medicine since 2012.

Research Focus

Dr. Diefenbach’s program of research has several foci: on the basic psychological level he is interested in the cognitive and affective factors as they relate to health behaviors and decision making. On an applied level, he is translating these basic findings into patient-centered interventions, with the goal to improve patient adjustment to disease and treatment and quality of life. Within this general framework, Dr. Diefenbach is conducting studies to examine and improve risk communication between patients and physicians, enhance decision making for a variety of at-risk populations, explore new ways to educate patients through innovative programs on multiple electronic platforms, and enhance symptom control during treatment. His research  follows strict methodological standards using both quantitative and qualitative methods, and is rigorously evidence based and transparent.


University of Mainz, Germany
Degree: BS
Field of Study: Psychology

University of Wisconsin, Madison
Degree: MS
Field of Study: Social/Health Psychology

Rutgers, The State University of New Jersey
Degree: PhD
Field of Study: Social/Health Psychology

Rutgers, The State University of New Jersey, The Institute for Health
Degree: Post-doctorial fellow
Field of Study: Health Care Policy and Aging

Fox Chase Cancer Center, The Division of Population Science
Degree: Advanced cancer training fellow
Field of Study: Psychosocial and Behavioral Medicine

Honors and Awards

2012-Present Treasurer/Secretary, Society of Behavioral Medicine
2012 Elected to fellow status for the Society of Behavioral Medicine
2010 C. Tracey Orleans Distinguished Service Award, Society of Behavioral Medicine
2009, 2010 Program Chair for the annual conference and scientific sessions Society of
Behavioral Medicine
1992 Dissertation Research Award from the American Psychological Association for
outstanding research proposal
1989, 1991 Travel Awards from the American Psychological Association to attend and
present research at the annual meetings
1986, 1987 Fulbright Fellowship to study Health Psychology at the University of
Wisconsin, Madison, WI

  1. Hoyt, M. A., Frost, D. M., Cohn, E., Millar, B. M., Diefenbach, M. A., & Revenson, T. A. (2017). “Gay men’s experiences with prostate cancer: Implications for future research.” Journal of Health Psychology. doi:10.1177/1359105317711491
  2. Leach, C. R., Troeschel, A. N., Wiatrek, D., Stanton, A. L., Diefenbach, M.A., Stein, K. D., Portier, K. (2017). “Preparedness and Cancer-Related Symptom Management among Cancer Survivors in the First Year Post-Treatment.” Annals of Behavioral Medicine. doi:10.1007/s12160-017-9880-6
  3. Hajizadeh, N., Basile, M. J., Kozikowski, A., Akerman, M., Liberman, T., McGinn, T., & Diefenbach, M. A. (2017). “Other Ways of Knowing: Considerations for Information Communication in Decision Aid Design.” Medical Decision Making. doi:10.1177/0272989×16683938
  4. Pollard, M. E., Moskowitz, A. J., Diefenbach, M. A., & Hall, S. J. (2016). “Cost-effectiveness analysis of treatments for metastatic castration resistant prostate cancer.” Asian Journal of Urology. doi:10.1016/j.ajur.2016.11.005
  5. Galsky, M.D., Stensland, K.D., Sfakianos, J.P., Mehrazin, R., Diefenbach, M.A., Mohamed, N., Tsao, C., Boffetta, P., Wiklund, P., Oh, W., Mazumdar, M., Ferket, B.S. “Comparative effectiveness of treatment strategies for bladder cancer with clinical evidence of regional lymph node involvement.” Journal of Clinical Oncology, 34(22), 2627-2635. Doi:10.1200/jco.2016.67.5033
  6. Miller-Halegoua, S., Bowen, D. J., Diefenbach, M. A., & Tercyak, K. P. (2016). “Creating the future of translational behavioral medicine.” Translational Behavioral Medicine Behav. Med. Pract. Policy Res., 6(2), 167-168. doi:10.1007/s13142-016-0421-9

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