War is often the trigger for mental illness, but the latest research reveals some unexpected effects of combat on post traumatic stress disorder (PTSD).
Feeling at home at war may seem like an oxymoron, but it has been reported for as long as wars have been. Now, research involving veterans of the war in Afghanistan suggests for the first time that some soldiers suffering from symptoms of PTSD before deployment improve during or after their combat duty. And another new study suggests that the size of a particular brain region— the amygdala— may predict which soldiers are at highest risk for the disorder.
Danish researchers studied 366 soldiers from Denmark before, during and after their tours of duty in Afghanistan for a paper published in Psychological Science. The vast majority of the veterans — 84% — showed few signs of PTSD at any time during the study.
Among the factors that distinguished the remaining PTSD sufferers was previous experience of trauma. These participants could be divided into four different groups depending on the way their symptoms changed during the course of service. In three of these groups, deployment was beneficial, reducing symptoms at some point during the study.
“By measuring PTSD symptoms in soldiers deployed to Afghanistan at five different time points, we find previously unseen patterns of PTSD development across time, and show the importance of childhood traumas —not combat— as predictors for lack of resilience,” says lead author Dorthe Berntsen of Aarhus University in Denmark.
Receiving harsh physical punishment and witnessing domestic violence were highly correlated with PTSD, confirming previous studies suggesting that severe stress is most toxic and traumatic when people feel they have no control over a situation, a common scenario for children raised in a chaotic and violent home.. “Such events may be especially traumatic because they are events in which caregivers play a central role,” says Berntsen, “In such cases, the child often has no one to turn to. Loneliness, isolation, negative self-appraisal, and a feeling of helplessness may be the result,” says Berntsen.
But some behaviors arising from those circumstances can be adaptive during war. Being more attuned to potential signals of threat, for example, or a having more sensitive startle response and the ability to dissociate yourself from particularly traumatic or violent situations involving combat and death can enhance survival during war. Terrorism expert Jessica Stern, herself a survivor of rape, described it this way, “If you think about what it takes to stay alive for a soldier — they call it PTSD when the soldier retires — but if he didn’t have hypervigilance and dissociation while on the battlefield, he’s a danger to himself and everybody else.”
That could explain in part why some soldiers with a history of trauma report feeling better during deployment: their “symptoms” are potentially useful during combat. Rather than debilitating them, they help them become better soldiers. But Berntsen found no relationship between the amount of combat exposure and the improvement seen in those with traumatic childhoods, so she suspects other aspects of the war experience, such as the camaraderie that develops during combat, may be involved. “More likely, being deployed in Afghanistan may have provided these people with a sense of commitment, a sense of being part of a team, a sense of recognition and comradeship,” she says.
But past traumatic experiences are likely only one of a myriad factors, along with genetic predisposition, that may make certain people more vulnerable to PTSD than others. In a separate study published in the Archives of General Psychiatry investigating such risk factors, researchers turned their attention to a more biological culprit in the brain.
The study included 200 American armed service members, most of whom had served in Iraq or Afghanistan after 9/11. Half of the participants had PTSD and scientists analyzed their brains to look for connections between PTSD and changes in a brain region known as the amygdala. This almond-shaped organ is best known for processing fear, but it is also linked with the experience of more positive emotions.
In animals, a smaller amygdala is associated with more robust fear-related learning — in which the animals respond a certain way to avoid the negative consequences of not doing so—which is also a characteristic associated with PTSD. But in humans, the link between amygdala size and PTSD isn’t as clear: some studies find a connection while others do not. Using a larger sample of soldiers, the authors hoped to determine whether the correlation was valid.
Their results support the idea that people with smaller amygdalas were more likely to have PTSD. But amygdala size wasn’t related to how much trauma the person had experienced, so the scientists suspect that smaller amygdalas are a risk factor, rather than a result of, trauma.
The findings could have important implications for military recruitment: if they are confirmed, and amygdala size can be consistently measured in a standardized way, those with smaller regions might be given extra social support to strengthen their resilience skills or perhaps kept out of direct combat roles entirely, depending on how high the risk proves to be. Similar precautions could be taken for those who suffered early childhood trauma. By understanding both environmental risk factors like childhood maltreatment and biological risk factors like amygdala size, a clearer picture of who is most at risk for PTSD is emerging, one that could help to protect soldiers from the worst symptoms in the future.