Vivid imprinting of memories of psychologically traumatizing events occurs in animals ranging from mice to humans. Mice subjected to inescapable foot shock or rats immobilized and then exposed to cats show signs analogous to PTSD after exposure to these horrific events. The signs shown include generalized fear and hypervigilance and continued discrete fear and avoidance of all aspects of the fear-inducing situation.
It is no surprise surprising that dogs and other mammals can develop PTSD, too, under similar life-threatening circumstances. The first case I saw, many years ago, was a dog that was shot by a Boston policeman who thought the dog was attacking him. The dog nearly died but was skillfully resuscitated by a local veterinary clinic and lived to see many other days.
Unfortunately, the dog’s mind did not heal as well as its body and following this incident of near death trauma it developed all the classical signs of PTSD. Hypervigilance, pronounced avoidance of anything associated with the event (police cars, policemen, sirens, flashing lights etc.), and what appeared to be nightmares causing it to sleep fitfully and only of accompanied by one of the two people in the household. Medication was the only solution to this dogs problems.
Later Gina, a dog of war, returned from a tour of duty in Iraq only a shadow of her former self. She was constantly anxious, looking out for trouble, and would not perform her duty of entering houses to flush out “insurgents” in training sessions. Her handler and the Army veterinarian suggested that she had PTSD, unthinkable at the time. So unthinkable that the story made National news.
By the time Gina’s story came out we had seen numerous cases of what appeared to be PTSD in dogs. Some occurred after abuse, some after hospitalization, and others after automobile accidents. Although many people think of PTSD as emerging after a psychologically traumatic event in the theater of war, any of life’s traumas can lead to PTSD in man and animals.
The Army took a close look at canine PTSD – or C-PTSD as they called it to distinguish it from the condition that occurred in the troops. Their definition was narrow as it applied to military working dogs only. Dogs showing signs had to have been present in a war situation, exposed to one or more notably traumatic events and then to show all the signs mention above, including inability to perform their normal duties. Interestingly, not all dogs going through closely conforming traumatic events developed PTSD. The incidence was about 5-10 percent. Those that do develop PTSD seem to be genetically programmed to respond that way. It’s the same for soldiers.
Numerous genes and epigenetic influences have been suggested as underlying susceptibility to PTSD. Most somehow influence the hypothalamic-pituitary-adrenal axis. Certainly, catecholamines are intimately involved in the imprinting of powerful negative memories as evidenced by studies showing that pre-treatment and even immediate post-treatment of animals prevents the development of PTSD-like signs.
There is also some evidence that traumatic early life experiences can set children up for PTSD through an environment-gene interaction. I would be a pound to a brass farthing that the same applies to animals and I am thinking especially of dogs from abusive backgrounds – what I would call dysfunctional early like experiences.
It seems a pity that with dogs of war being such a good model for the study of PTSD in people, that funding has not been forthcoming in this direction. Dog breeds are especially good for genetic studies because they are effectively closed populations.
Dogs are also good for therapeutic trials. Through trial and error, we have found that selective serotonin reuptake blockers and adrenergic blockers help dogs with PTSD. The same is true for people. Novel (but safe) treatments applied first to dogs with PTSD would provide pilot data on which human clinical trials could be based.