Page last updated at 23:05 GMT, Thursday, 2 April 2009 00:05 UK
Scientists say they are moving ever closer to being able to diagnose Post Traumatic Stress Disorder (PTSD) using a brain scanner.
Research to be presented to the World Psychiatric Association congress in Florence suggests differences in the brain activity of PTSD sufferers.
Over 40 US soldiers who had served in Iraq or Afghanistan were tested – about half of whom had a diagnosis of PTSD.
Their brains were examined with an MRI scanner as they performed memory tests.
The term PTSD is used to describe a range of psychological symptoms people may experience following a traumatic, usually life-threatening, event. It is seen most commonly in those who have been on active service.
Researchers at Duke University in the US presented 42 soldiers, both male and female, with photographs of three similar faces.
They were then showed pictures of a combat scene, a non-combat scene – such as as man playing a trombone for instance – or a digitally scrambled picture.
Finally, they were shown a photograph of a face again and asked whether they had just seen it.