First responders are commonly exposed to life-threatening situations. As a result, they face an increased risk of developing psychological and physical health problems including posttraumatic stress disorder (PTSD) and sleep disturbances.
In fact, PTSD affects anywhere from 5 to 40% of first responders, rates substantially greater than the general population. Previous research has suggested long-term effects between PTSD and sleep disturbances, yet little is known about how PTSD and sleep interact with one another on a day-to-day basis, nor how subdimensions of PTSD (hyperarousal, numbing, avoidance, and intrusion) and sleep uniquely affect one another in the short-term.
In a study published in the December 2019 issue of Journal of Occupational Health Psychology, Dietch and colleagues tracked daily sleep and PTSD in 202 participants (M age 54 [SD=10]; 83% male) who worked or volunteered in rescue, recovery, restoration, or cleanup of the World Trade Center disaster. Participants were recruited from the Long Island site of the World Trade Center Health Program, and approximately 18% of the sample had a current PTSD diagnosis confirmed by structured clinical interview.
Participants completed baseline questionnaires followed by 7 days of ecological momentary assessment surveys on a study-provided iPod. The daily measures asked participants to answer questions about the previous night's sleep quality and quantity each morning and rate their PTSD symptoms three times a day.
Several important findings emerged.
First, PTSD symptoms during the day predicted shorter sleep duration and worse subjective sleep quality that night. For sleep duration, the primary symptom dimension driving this relationship was daytime numbing. For sleep quality, all dimensions of PTSD contributed to the relationship, but daytime numbing was the strongest predictor.
Daytime numbing could contribute to sleep disturbances in several ways including disengagement from enjoyable activities, decreased circadian signaling, a diminished sleep drive, engagement in sleep-incompatible behaviors, and emotion dysregulation.
There was also evidence for a reverse relationship: sleep duration at night predicted increased PTSD symptoms the next day, with sleep mostly affecting symptoms of intrusions. Short sleep duration could potentially contribute to intrusions the next day via a reduced opportunity for memory consolidation during the night. Sleep quality did not predict PTSD symptoms the next day.
This study points to a critical dynamic between PTSD and sleep in first responders, even in the very short term, and highlights a short-term pathway that may explain how symptoms are maintained.
This work also underscores the opportunity to develop and implement highly targeted momentary interventions that disrupt this dynamic and potentially improve outcomes for first responders and other high-risk populations.
Citation
- Dietch, J. R., Ruggero, C. J., Schuler, K., Taylor, D. J., Luft, B. J., & Kotov, R. (2019). Posttraumatic stress disorder symptoms and sleep in the daily lives of World Trade Center responders. Journal of Occupational Health Psychology, 24(6), 689–702. https://dx.doi.org/10.1037/ocp0000158
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