(Mike Hoff/Flickr)

A new study may help identify individuals who are more vulnerable to stress disorders after traumatic events.

The study, published in the December issues of Biological Psychiatry, looked at the level of a stress hormone called cortisol in 296 police recruits when they woke up and then 30 minutes later. Over several years, the study found, those officers with higher cortisol levels were more likely to have stressful reactions around traumatic events.

Lead author Sabra Inslicht, a psychologist with the San Francisco Veterans Affairs Medical Center, says the study is the first of its kind to look at hormone levels before traumatic events.

"We have an opportunity to look at individuals before they were ever exposed to trauma and to see if there is something different before they go into the stressful environment - and will that affect future responses."

Inslicht say the ultimate goal is to develop a profile of risk and resilience that would identify individuals most at risk in order to be able to intervene early on. She says the study could lead to insights into risk factors for conditions like Post Traumatic Stress Disorder.

More research is still needed, Inslicht says, and it's necessary to replicate the study in civilians because police officers may be more resilient than the general population.

The study was conducted by researchers at the San Francisco VA Medical Center, UCSF, and NYU's Langone Medical Center, and was supported by the National Institute of Mental Health and the Department of Veterans Affairs.