Increased Incidence Rate of Trauma- and Stressor-related Disorders in Denmark After the Breivik Attacks in Norway.

Abstract

On 22 July 2011, Anders Breivik killed 77 adults and children in Norway. Having recently documented increases in the incidence of trauma- and stressor-related disorders in Denmark after the 9/11 attacks, we hypothesized that the Breivik attacks-due to their geographic proximity-would be followed by even larger increases in Denmark. Using population-based data from the Danish Psychiatric Central Research Register (1995-2012), we conducted an intervention analysis of the change in the incidence of trauma- and stressor-related disorders after the Breivik attacks. The incidence rate increased by 16% over the following 1½ years after the Breivik attacks, corresponding to 2736 additional cases. In comparison, 9/11 was followed by a 4% increase. We also present evidence of a subsequent surge in incidence stimulated by media attention. This study bolsters previous findings on extra-national consequences of terrorism and indicates that geographic proximity and media coverage may exacerbate effects.