Proximity to terror and post-traumatic stress: a follow-up survey of governmental employees after the 2011 Oslo bombing attack

OBJECTIVE To assess the prevalence of post-traumatic stress disorder (PTSD) symptoms among governmental employees after the 2011 Oslo bombing attack targeted towards the Norwegian Ministries, and to explore the importance of proximity to the bomb explosion as a predictor of PTSD. DESIGN A cross-sectional study. SETTING Data were collected from a survey 10 months after the Oslo bombing on 22 July 2011. PARTICIPANTS A total of 3520 employees were invited to the study. Net samples comprised 1927 employees in 14 of the 17 Norwegian Ministries. OUTCOME MEASURES The employees reported where they were at the time of the explosion. PTSD was assessed with the Norwegian version of the PTSD checklist (PCL). RESULTS A total of 207 of the 1881 (11%) ministerial employees who completed the survey were present at work when the bomb exploded. Of these, a quarter (24%, 95% CI 18.4 to 30.0) had symptom levels equivalent to PTSD, while the prevalence was approximately 4% among those not present at work. In the latter group the prevalence was similar irrespective of whether their location was in Oslo, other places in Norway or abroad. Leadership responsibility was associated with lower risk for PTSD. CONCLUSIONS The risk of PTSD is mainly associated with being present at work at the time of a terror attack. For those not present at work, the risk of PTSD is low and independent of proximity to the terror scene. The findings may have implications for planning and priority of healthcare services after a work place terror attack.