Among men and women who served in Iraq and Afghanistan, Post-Traumatic Stress Disorder is common and can occur with or without a concussion. To merit a diagnosis of PTSD, a service member must have experienced not only a horrific, stressful, traumatic event, but also must re-experience that trauma persistently, avoid reminders of the event (certain places or objects, for example), and display increased arousal. With PTSD, these symptoms persist longer than a month and interfere materially with the service member's life. Neuropsychologist Cynthia Boyd describes a corpsman with multiple blast exposures who re-experiences a trauma in a manner consistent with PTSD:

Life After Five Deployments and TBI

"He thought they were under fire. He went in a full on flashback…"