The role of automatic defensive responses in the development of posttraumatic stress symptoms in police recruits: protocol of a prospective study

Figures & data

Figure 1. Design of the Police-in-Action study. A total of 340 police recruits and 85 control participants will be tested twice, at baseline (wave 1) and at follow-up (wave 2), which are approximately 15 months apart. Between assessment waves, police recruits (but not controls) experience two emergency aid periods as part of their normal training, each lasting four months. CAPS = clinician-administered PTSD scale.

Figure 2. Overview of the testing days. The wave 1 and wave 2 assessments consist of similar testing procedures, except for two minor differences in Behavioural session 1 and the Interview (see figure). MRI = magnetic resonance imaging.

Table 1. Inclusion and exclusion criteria.

Inclusion criteria
1. Between 18 and 45 years of age
2. Normal or corrected-to-normal vision
3. Normal uncorrected hearing
4. Body mass index between 18.5 and 30
5. Willingness and ability to give written informed consent
Exclusion criteria
1. Average use of more than three alcoholic beverages daily
2. Average use of psychotropic medication or recreational drugs weekly or more
3. Use of psychotropic medication
4. Recreational drugs use within 72 hours prior to testing, or alcohol use within 24 hours prior to testing
5. Current psychiatric or neurological disorder, or within the last three months
6. Regular use of systemic corticosteroids
7. Metal objects or fragments in or around the body
8. Medical plaster that cannot be taken off
9. History of neurological treatment or current neurological treatment
10. History of endocrine treatment or current endocrine treatment
11. History of head surgery
12. Current periodontitis
13. Claustrophobia
14. Epilepsy
15. Pregnancy
Additional exclusion criteria for control participants
16. Experience in law enforcement or military
17. Training or occupation involving potential trauma exposure, e.g. military or healthcare occupation