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Fire fighters routinely risk their lives to protect the public. Over 1 million fire fighters in the United States alone sign up for this dangerous profession to protect people, wildlands, and property despite known threats to their healthy, safety, and wellbeing. While our prior research points to remarkable levels of resilience in this population given their enormous exposure to a variety of traumatic experiences (Gulliver et al., in press), a minority of fire fighters do develop posttraumatic stress disorder (PTSD) or related mental health problems. This points toward the presence of individual-level risk factors that drives this variability in responses to traumatic events.

Much prior research on risk factors for PTSD has focused on demographic factors such as age and gender or to characteristics of the trauma exposure. While important, such factors either account for very small amounts of variability in risk or are not modifiable and therefore do not inform risk mitigation or intervention approaches. Personality has been relatively understudied as a risk factor for PTSD, particularly in prospective research where personality is measured prior to trauma exposure. Fire fighters thus represent an ideal population in which to study the influence of personality on the development of PTSD and related symptoms. Fire fighters can be assessed upon entry into the profession, prior to being exposed to traumatic events, and then assessed over long follow-up periods because they typically remain with the same department for many years.

Among personality factors, negative emotionality (NEM), also commonly referred to as neuroticism, predicts the later development of PTSD in other trauma-exposed populations. NEM refers to how often and how intensely people tend to experience emotions that are typically characterized as negative (e.g., anger, sadness, fear, guilt). Higher NEM predicts greater risk for a range of mental health problems and for cardiovascular disease. While previously thought to be static and unmodifiable, emerging evidence points toward personality as a malleable predictor of a range of health, employment, and other consequential long-range outcomes (Bleidorn et al., 2019; Roberts et al., 2017). Yet, personality has not been prospectively studied in relation to PTSD in fire fighters.

The goal of this study was to test whether NEM measured prior to employment as fire fighters predicted PTSD symptom severity over time by influencing how FFs respond to the frequent trauma exposure endemic to the profession. In this first prospective study of the development of PTSD symptoms in professional firefighters, 322 newly hired fire fighters were recruited from seven urban fire training academies across the United States and assessed over their first three years of fire service. We assessed NEM during the fire academy and trauma exposure and both self-reported and clinician-rated PTSD symptoms at 1-, 2-, and 3-year follow-ups.

As we expected, both higher level of trauma exposure and greater NEM measured during the fire academy predicted greater PTSD symptoms over time. The key finding in this study was that NEM interacted with, or moderated, the effect of trauma exposure on clinician-rated PTSD symptoms across two different measures of types of trauma exposure at both 1-year and 3-year follow-up, though not at 2-year follow-up, and not for self-reported PTSD symptoms. It is important to Our interpretation is that we did not find this effect for self-reported PTSD symptoms because the relationship between self-reported symptoms, and NEM, which is also measured via self-report, was so high that it made it difficult to detect the interaction effect. It is unclear why the interaction was not present at 2-year follow-up.


In this first study of its kind in this important population, we think it is important to interpret the overall pattern of findings in order to stimulate further research. These findings indicate that NEM, assessed upon entry into a high-risk occupation, is useful for predicting the development of PTSD symptoms. 

Reference Article

Meyer, E.C., Zimering, R.T., Knight, J., Morissette, S.B., Kamholz, B.W., Coe, E., Carpenter, T.P., Keane, T.M., Kimbrel, N.A. and Gulliver, S.B., 2020. Negative Emotionality Interacts with Trauma Exposure to Prospectively Predict Posttraumatic Stress Disorder Symptoms During Firefighters’ First 3 Years of ServiceJournal of Traumatic Stress.

Discussion Questions

  • What is the best study design for researching the influence of personality on posttraumatic stress symptoms and why?
  • What are some ways these findings may be used by leaders in fire service?
  • Are the findings surprising to you or not? Why?

About the Authors

Eric Meyer, PhD is Professor and Director of Clinical Rehabilitation and Mental Health Counseling in the Department of Rehabilitation Science and Technology at the University of Pittsburgh. He studies risk, resilience, and recovery related to complex combinations of mental and physical health challenges in emergency responders, military populations, and in those living with disabilities. Dr. Meyer may be contacted at ECM77@pitt.edu. Twitter: @EricMeyerPhD
Suzy Bird Gulliver, PhD is Director of the Warriors Research Institute at Baylor Scott & White Health and Professor of Psychiatry and Behavioral Science at Texas A&M Health Science Center, College of Medicine. Her work focuses on innovative methods of meeting the behavioral health needs of emergency responders, military populations, and their families, including the role of peer support. Dr. Gulliver may be contacted at Suzy.Gulliver@bswhealth.org. Twitter: @SuzyGulliverPhD


Gulliver, S.B., Zimering, R.T., Knight, J., Morissette, S.B., Kamholz, B.W., Pennington, M.L., Dobani, F., Carpenter, T.P., Kimbrel, N.A., Keane, T.M., & Meyer, E.C. (In press). A prospective study of firefighters’ PTSD and depression symptoms: The first three years of service. Psychological Trauma: Theory, Research, Practice, and Policy.
Bleidorn, W., Hill, P.L., Back, M.D., Denissen, J.J.A., Hennecke, M., Hopwood, C.J., Jokela, M., Kandler, C., Lucas, R.E., Luhmann, M., Orth, U., Wagner, J., Wrzus, C., Zimmerman, J., & Roberts, B. (2019). The policy relevance of personality traits. American Psychologist, 74, 1056-1067. doi: 10.1037/amp0000503.
Roberts, B. W., Luo, J., Briley, D. A., Chow, P. I., Su, R., & Hill, P. L. (2017). A systematic review of personality trait change through intervention. Psychological Bulletin, 143, 117–141. http://dx.doi.org/10 .1037/bul0000088