Post-Traumatic Stress Disorder (PTSD) has become an increasingly widely recognized and accepted response to combat, natural disasters and other traumatic experiences.
PTSD is recognized by the DSM-IV (the standard handbook for diagnosis of mental illness). It is defined on the National Institute for Mental Health (NIMH) website:
Post-Traumatic Stress Disorder, PTSD, is an anxiety disorder that can develop after exposure to a terrifying event or ordeal in which grave physical harm occurred or was threatened. Traumatic events that may trigger PTSD include violent personal assaults, natural or human-caused disasters, accidents, or military combat.
Recent experience in Afghanistan indicates that dogs can also suffer from PTSD. According to The Wall Street Journal, Gunner "a brown-eyed, floppy-eared yellow Lab" is that kind of dog:
He graduated from bomb-dog school in Virginia. He could hunt and tolerate gunfire. He could sniff out explosives, including the homemade ammonium-nitrate fertilizer bombs that inflict most allied casualties in Afghanistan. But he was skittish even before he arrived in the combat zone in October and was posted to a front-line battalion.
According to his official record Gunner "is not mission capable and is a liability if he is to leave the wire." Maj. Rob McLellan, 33-year-old operations officer of the 2nd Combat Engineer Battalion expresses it in laymen's terms, he says, the stress sometimes "weighs a dog down to the point where the dog just snaps."
Army veterinarian Capt. Michael Bellin, who works with the Marine canine units concurs, "I think it [canine PTSD] is possible, depending on what they went through." Canine PTSD has also been confirmed by other studies.
Also, like human PTSD, it strikes different individuals at different times and after different burdens of stress. For Gunner training was stressful although he completed it successfully, but living with the constant noise of artillery, aircraft and small arms fire rendered him unable to leave his kennel.
Corporal McCoy puts it simply, "Gunner's a lover, not a fighter."