Previous Trauma Exposure and PTSD Symptoms as Predictors of Subjective and Biological Response to Stress

Article excerpt

Objective: The immediate and long-term effects of traumatic exposure and subsequent posttraumatic stress reactions in people in high-risk occupations are well-documented. What is less evident is the impact of this traumatic exposure and subsequent traumatic stress symptoms on workers' response to acute stress situations. This study aimed to examine the association between prior traumatic exposure related to policing, current posttraumatic stress symptoms and biological markers of stress, and subjective appraisal of stress before, during, and after exposure to acutely stressful stimuli.

Method: A stressful policing situation was created through the use of a video simulator room. Participants' responses to the simulated emergency were evaluated by monitoring heart rate, collecting salivatory samples for cortisol analysis, and repeated administration of a subjective measure of anxiety.

Results: Biological indicators of stress, as measured by cortisol level and heart rate, were not associated with previous trauma exposure or trauma symptoms; however, biological response was associated with subjective anxiety. Vulnerability to psychological stress responses during an acute stress situation was also associated with lower levels of social support, previous traumatic exposures, and preexisting symptoms of traumatic stress. The importance of these factors became more pronounced as time progressed after the event.

Conclusion: Previous trauma exposure did not put individuals at increased risk of biological distress during an acute stress situation. However, previous trauma and reduced social supports were associated with continuing psychological distress, confirming previous research and raising concerns about the cumulative negative effects of traumatic exposure on psychological health in emergency responders.

(Can J Psychiatry 2007;52:675-683)

Clinical Implications

* Emergency responders enter training with previous traumatic exposures, potentially increasing vulnerability to stress and distress throughout their career.

* Prior trauma exposure did not increase psychological distress during an acute situation, suggesting individuals can manage crisis situations.

* Prior trauma exposure was associated with higher psychological distress in follow-up, suggesting possible risk and potential need for intervention.

Limitations

* This research was conducted on police recruits and may not be generalizable to other populations.

* The acute stress situation was a simulated, not real-life, exposure.

* Physiological and psychological distress was only measured within a short time frame, and thus long-term follow-up will be useful.

Key Words: trauma, stress, cortisol, heart rate

Abbreviations used in this article

bpm beats per minute

CIHQ Critical Incident History Questionnaire

FATS Fireams Training Systems

HPA hypothalamic-pituitary-adrenal axis

IES Impact of Event Scale

IES-R Impact of Event Scale-Revised

OPC Ontario Police College

PTSD posttraumatic stress disorder

SD standard deviation

SPS Social Provisions Scale

STAI State-Trait Anxiety Inventory

An important body of literature explores the issue of work-related distress in police officers and the presence of posttraumatic stress symptoms subsequent to exposure to critical events in the line of duty. Events most likely to cause high levels of traumatic stress include exposure to the gruesome death of others,1-4 the need to discharge a firearm, especially if it results in the death or injury of others,5"7 and threats to themselves.3'4'8 Symptoms reported include sleep loss,5'9 high levels of intrusion and avoidance symptoms such as fears and flashbacks, 1,2's and depression.1 The degree of symptoms experienced by officers has been found to be related to the severity and proximity of trauma exposure10 and the number of successive traumatic events to which they are exposed. …