Gene associated with threat vigilance can protect against post-traumatic stress

PhD student Ilan Wald and Prof. Yair Bar-Haim, of Tel Aviv University, have together discovered that Post-traumatic Stress Disorder (PTSD) symptoms can be predicted prior to war deployment by the level of threat avoidance before departure. Threat-related attention bias has hence been found to be moderated by a certain gene. These findings have important implications for identifying people at risk, thereby preventing high rates of post-combat PTSD in the future.

PTSD is an anxiety disorder that may develop after exposure to a traumatic event. Over 1000 soldiers from the Israeli Defence Forces were tested on their attention bias towards or away from threat at three points in time: just after recruitment, prior to deployment, and after combat. For the soldiers who had been exposed to high-stress situations during combat, threat vigilance prior to deployment was found to protect against post-combat PTSD symptoms.

A genotype of the serotonin transporter gene (low-transcript type) is associated with high threat vigilance. Bias towards threat, however, in everyday situations, is thought to be linked to increased risk for anxiety disorder – the opposite of what this study suggests. A possible explanation for the paradoxical findings may be that while threat vigilance is inconvenient in safe situations, it is necessary in high-stress situations. Being able to adapt one’s threat-related attention bias to the environment, is therefore the best protection against post-combat PTSD symptoms. The shifting of attention bias can be trained prior to deployment, and may consequently help prevent cases of PTSD in the future.

Reference: Ilan Wald et al. (2013). Attention to Threats and Combat-Related Posttraumatic Stress Symptoms: Prospective  Associations and Modulations by the Serotonin Transporter Gene. JAMA Psychiatry, doi: 10.1001/2013.jamapsychiatry.188.