Many soldiers carry the psychological weight of taking another life — but is killing always an unbearable burden, or can some soldiers rationalise it and find ways to cope?
A study of more than 14,600 Norwegian Armed Forces veterans suggests that killing in combat is not always detrimental to a soldier’s mental health. Context appears to be key: veterans who killed during peacekeeping missions reported worse outcomes, those who killed in active combat did not show significant signs of psychological harm.
This research contradicts previous theories that killing is inherently damaging to soldiers’ mental health.
“Killing another person does not in itself seem to be something that goes against human nature, and it doesn’t necessarily harm the mental health of the person who does it,” says Andreas Nordstrand, a clinical psychologist and head of research and development at the Institute of Military Psychiatry, Norwegian Armed Forces.
While the findings may be viewed as controversial, the researchers say they underscore the responsibility of political and military leadership to clarify rules of engagement and mission objectives. Ensuring soldiers feel aligned with societal and mission norms could help protect them from long-term mental health repercussions.
The study compared Norwegian veterans who served in Lebanon—largely on peacekeeping missions with lower levels of direct combat—to those who served in Afghanistan, where they more frequently faced aggressive engagements.
Drawing on data from 10,605 Lebanon veterans and 4,053 Afghanistan veterans, the researchers examined the prevalence of mental health issues such as post-traumatic stress disorder (PTSD), depression, insomnia, anxiety, and alcohol misuse, as well as overall quality of life. In the study, 156 Lebanon veterans (1.47%) reported having killed in combat, compared with 532 Afghanistan veterans (13.14%), reflecting differences in combat exposure between the two groups.
These findings, published in Armed Forces & Society, revealed starkly different outcomes between the two cohorts.
“Taking a life in combat was a key factor among the veterans who had served in Lebanon. The veterans who had killed someone in combat were more likely to experience mental health problems, increased alcohol consumption and reduced quality of life later on,” Nordstrand explains.
“[But] for the Afghanistan veterans, taking a life had no subsequent impact on their mental well-being.”
“Our findings indicate that whether taking a life subsequently has a negative impact on mental health and quality of life is highly context-dependent,” says Nordstrand. “We believe this supports the view that it is primarily violations of group norms and mission guidelines that make actions like killing, harmful.”
War mode vs peace mentality
Evolutionary psychologist Professor Leif Edward Ottesen Kennair, also involved in the research, emphasises the role of a soldier’s mindset. If service members anticipate combat and interpret their actions as part of an accepted “war mode,” they may be better psychologically prepared for the consequences of lethal force.
“The mindset with which soldiers approach a mission determines whether they expect, are prepared for and interpret the intense aspects of the role,” he says. “If they are in war mode and fully aware of it, they will deal with it completely differently. They experience events and actions differently than if they are unprepared or have a peace mentality.”
Nordstrom says the findings of this sensitive topic may be perceived as somewhat taboo.
“Soldiers kill and being able to do that is actually a key part of their job. The findings are a clear call to take both political and collective responsibility when sending soldiers on dangerous missions, ensuring that they do not feel as though they have done something that goes against the norms of the society they are part of.”
Creating super soldiers
