Short summary

We examine sex/gender differences in acute psychological, physiological, and endocrinological trauma reactions and their impact on PTSD in accident victims treated at the Hospital South West Jutland over a 1-year period. Biological and medical data was collected at the scene of the accident (T1), upon arrival at the hospital (T2), on the first morning following the accident (T3), and once the patient was lucid (T4). Questionnaire data was collected after 3 (FU1) and 6 (T2) months.

Rationale

Each year in Denmark, 1500-2000 people get seriously hurt in traffic, twice as many men as women. Traffic accidents and similar severe accidents can be traumatic for the victims, and around 20-45% go on to develop posttraumatic stress disorder, PTSD. PTSDis a mental disorder characterised by symptoms of re-experiencing the accident, avoidance of reminders of the accident, and hyper-vigilance and stress. PTSD is associated with a multitude of psychological and somatic problems and disorders, including anxiety, depression, chronic pain, low quality of life, reduced functioning, and early death. There are significant sex differences in PTSD. The risk of developing PTSD is approximately twice as high in women as in men and research suggests that the same risk factors may not be associated with symptom development in women and men. Sex differences in PTSD are believed to be related to sex differences in the peritraumatic trauma response, meaning that sex differences in women's and men's acute physiological, endocrinological, immunological, and psychological reactions to severe accidents are thought to affect their subsequent risk of developing PTSD. Men tend to respond to traumatic events with an immediate activation of the sympathetic nervous system (SNS), characterised by an increase in blood pressure, heart rate, and respiratory rate - a so-called hyperarousal response. This response prepares the body for either fighting or fleeing (the fight-or-flight response). In contrast, there is evidence that women are more likely to respond to immediate threat with physiological hypoarousal: an immediate suppression of blood pressure, heart rate, and respiratory rates. Sex differences in these physiological responses are believed to be linked to sex differences in endocrinological responses in the HPA axis, the immunological system, and the psychological trauma response. For example, women are much more likely than men to respond to traumatic events by seeking safety from and caring for others (the tend-and-befriend response) and by dissociating. Dissociation is considered a psychological defence against imminent threat and is characterised by the disintegration of aspects of consciousness thar are normally integrated (e.g. memory, identity, attention, perception). The resulting experiences may include time slowing down or speeding up, derealisation, depersonalisation, out-of-body experiences, and tonic immobility where the victim is unable to move or call out for help. Though research is lacking, especially in the acute posttraumatic phase, both dissociation and the tend-and-befriend response have been linked to hypoarousal. To better understand the importance of sex and gender in the development of PTSD, it is important to look at both biological and socio-cultural aspects of both. These include factors such as the gonadal hormones oestrogen, oestradiol, LH, FSH, and testosterone, the peptide oxytocin, gender role, gender identity, masculinity, femininity, and sexual identity. Knowledge about such such sex differences has important implications for early identification and prevention of PTSD following serious accidents. Many of the neurotransmitters believed to be involved in the acute trauma response and subsequent symptom development can be influences therapeutically through both psychological and pharmacological interventions. Thus, by adding to our knowledge of the importance of such factors for the development of PTSD and other trauma-related disorders we can increase our opportunity to reduce the substantial personal, social, and societal costs associated with trauma. Unfortunately, research on the interactions between the physiological, endocrinological, and psychological reactions to traumatic events and potential sex differences in these responses and their relevance to PTSD is rare.

Description of the cohort

Adult men and women arriving at the Hospital of South-West Jutland trauma department after having been in an accident. Exclusion criteria were age <18, victims of violence or self-harm. Only patients willing and able to provide written consent were included.

Data and biological material

Upon arrival at the hospital, blood samples were collected. The following morning, blood and saliva samples were collected. Only data from patients who agreed to participate in the study was kept and analysed (biological data from non-participants was destroyed). Data was extracted from hospital and ambulance records. Additional data was collected by the project nurse through interview with the participant following inclusion in the study and via questionnaire within a few days of the accident and again at 3 and 6 month follow-up.

Collaborating researchers and departments

Department of Psychology, Research Center for Psychotraumatology, University of Southern Denmark

• Dorte M. Christiansen
• Ask Elklit

Research Unit in Emergency Medicine, Hospital of South West Jutland, Esbjerg

• Professor Mikkel Brabrand, MD, PhD
• Research coordinator Line E. L. Laugesen
• Project nurse Mette R. Kristensen

Department of Orthopaedics, Hospital of South West Jutland, Esbjerg

• Professor Niels Wedderkop, MD, PhD
• Chief physician Lars T. Hansen. MD

Department of Clinical Biochemistry, Hospital of South West Jutland, Esbjerg

• Laboratory technician project manager Gunhild B. Nielsen

Prehospital Research Unit, Department of Regional Health Research, University of Southern Denmark

• Professor Søren Mikkelsen, MD, PhD

Department of Endocrinology, Odense University Hospital

• Ass. professor Dorte Glintborg, MD PhD
• Professor Marianne S. Andersen, MD PhD