US scientists have discovered a way to diagnose post-traumatic stress disorder (PTSD) by measuring the brain's magnetic fields.
Conventional brain scans do not reveal whether or not a person has the disorder, but the new technique demonstrated 90% accuracy when tested on a group of war veterans.
Symptoms of PTSD can include angry moods, jumpiness, recurring nightmares and flashbacks to psychologically traumatic events. Sufferers have usually been exposed to war, natural disasters, violent crime or accidents.
The 74 test subjects with PTSD had served either in World War Two, Vietnam, Afghanistan or Iraq, and were identified from a group of 250 non-sufferers by a technique called magnetoencephalography (MEG).
This analyses magnetic charges released by synchronous connections between brain cell populations and is the first working objective test.
Led by Professor Apostolos Georgopoulos, researchers at the Minneapolis Veteran Affairs Medical Center also discovered MEG revealed correlations between the severity of symptoms and the certainty of their predictions.
They wrote in the Journal of Neural Engineering: "The excellent results obtained offer major promise for the usefulness of the synchronous neural interactions test for differential diagnosis as well as for monitoring disease progression and for evaluating the effects of psychological and/or drug treatments."