Post-traumatic stress disorder of serving Army personnel and military veterans has increased in the last 10 years, a new study suggests.
Most sufferers were veterans who saw active combat; 17% reported symptoms of probable PTSD.
Experts said the delayed onset of the illness, and the loss of support when leaving the army, were probable causes.
And more veterans are seeking treatment, as awareness of PTSD has increased.
The study of nearly 9,000 of the military, by King's College London, is published in the British Journal of Psychiatry. It shows that PTSD in the military increased from 4% in 2004-5 to 6% in 2014-16.
Among veterans deployed in a combat role to Iraq or Afghanistan, 17% reported symptoms suggesting probable PTSD, compared to 6% deployed in support roles such as doctors and aircrew.
Lead author Dr Sharon Stevelink, from the Institute of Psychology, Psychiatry & Neuroscience (IoPPN) at King's College, said: "For the first time we have identified that the risk of PTSD for veterans deployed in conflicts was substantially higher than the risk for those still serving.
"While the increase among veterans is a concern, not every veteran has been deployed and in general only about one in three would have been in a combat role."
The findings are from the third phase of a major study which has been running since 2003.
The latest phase of the study surveyed participants between 2014 and 2016. 62% of them had deployed to Iraq or Afghanistan, and the average age was 40.
The study also found that common mental health disorders - like anxiety and depression - had remained largely static at 22%.
Alcohol misuse remained a common problem, but fell from 15% to 10%.
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