Eliza Browning
AC360° Associate Producer

The suspect in the Fort Hood shootings, Maj. Nidal Malik Hasan, is a mental-health professional who worked to help others in high-stress situations. A soldier who served two tours in Iraq and is awaiting medical retirement for chronic PTSD referred to Hasan as "a soldier's soldier who cared about our mental health."

The impact on therapists who work with traumatized individuals is known as vicarious traumatization – or compassion fatigue. The motive behind Hasan’s attack is uncertain, but some believe that in addition to working with people suffering from mental health problems, he too may have been troubled.

This has left many of us at AC360° wondering about Post-Traumatic Stress Disorder (PTSD) and whether or not it played a role in the shooting. What we know for sure, however, is that the shooting at Fort Hood could give rise to PTSD among many of the people impacted.

Here are some details on PTSD compiled by the Mayo Clinic:

Post-traumatic stress disorder (PTSD) is a type of anxiety disorder that's triggered by a traumatic event. You can develop post-traumatic stress disorder when you experience or witness an event that causes intense fear, helplessness or horror.

Many people who are involved in traumatic events have a brief period of difficulty adjusting and coping. But with time and healthy coping methods, such traumatic reactions usually get better. In some cases, though, the symptoms can get worse or last for months or even years. Sometimes they may completely disrupt your life. In these cases, you may have post-traumatic stress disorder.

Take a look at some of the symptoms, causes and treatments to deal with PTSD.