SCHWEINFURT, Germany -- Soldiers returning from a war zone often have difficulty adjusting to life at home.

They may be easily irritated, react suddenly and unexpectedly to loud noises, or become withdrawn and unwilling to communicate.

Experts say people who experience a frightening, traumatic event -- such as combat -- often react with heightened levels of arousal and fear. Memories of the event are painful, and may trigger a fear response similar to that caused by the original event.

These heightened fear responses are normal, said social work care manager Rick Thompson, "but most people, over a period of time, usually around three months, get back to normal."

Post Traumatic Stress Disorder occurs when a person gets "stuck" in the grip of that fear. The cause, though not completely understood, appears to be both neurobiological -- a result of chemical reactions in the brain -- and is also related to the way the patient thinks.

The chemical aspect of the disorder can be treated with medications, but the thought processes that foster and perpetuate the disorder are often difficult to change.

"A Soldier thinking that their symptoms are related to weakness -- that's the kind of belief that isn't going to be helpful, and tends to keep you stuck," Thompson said.

The symptoms of PTSD and minor Traumatic Brain Injury may overlap, and tests designed to uncover one, such as the Automated Neurobiological Assessment Metrics for mTBI, often detect Soldiers suffering from the other, said Lt. Col. Daniel Duecker, the Schweinfurt health clinic commander.

On the down side, overlapping symptoms between PTSD and many other psychological disorders such as major depression can complicate diagnosis.

"With PTSD, you have to have some sort of scary event history, and there has to be some sort of re-experiencing symptoms," Thompson said.

This re-experiencing most often occurs as intrusive memories.

"With some people it's flashbacks, but it's not all that common. With a lot of people, it's nightmares ... That symptom category is something that does not happen with mTBI or depression," Thompson explained.

In years past, Soldiers often felt there was a stigma in seeking treatment for PTSD, but medical professionals say the military community is working hard to change those impressions. Programs such as "Battlemind," which provides pre- and post-deployment training on the psychological effects of deployment, are now a routine part of the deployment cycle, and screening for PTSD is conducted as well.

"The Battlemind program helps 'reframe' the types of training and thinking that were required for Soldier survivability in a war zone" in a way that will help the Soldier cope with life outside of that area, Thompson explained.

In a war zone emotional suppression may be necessary in dangerous situations. But continuing to deny expression can be maladaptive once outside the war zone, and cause a Soldier to become detached or seem uncaring. This can lead to problems in coping, exacerbate existing post-traumatic reactions and frustrate family members.

Altering those thought patterns is one step toward avoiding or healing PTSD.