Post-traumatic stress disorder (PTSD) is a condition in which an animal exhibits excessive and maladaptive fear responses to a traumatic stimulus. When the animal encounters a situation from which it cannot escape or cope, it may display intense avoidance behaviors, anxiety, or exaggerated reactions. This process is associated with activation of the sympathetic branch of the autonomic nervous system and is perceived by the animal as an uncontrollable threat. During this disorder, agitation and panic may be observed. Additionally, the animal’s sensitivity to pain and social stimuli increases. Depending on the associations formed between the traumatic event and its context, triggering stimuli may either generalize or remain specific. The response may be elicited by a particular stimulus or reactivated by memories of similar past experiences.

The development of PTSD is generally linked to a social or environmental trigger; however, in some cases, the trigger may not be clearly identifiable. Nevertheless, careful observation can help determine these triggers.

Common and Nonspecific Clinical Signs

The clinical signs of PTSD may not appear immediately after the traumatic event. Symptoms can develop weeks or even longer after the incident, and their severity may fluctuate over time. Nonspecific signs include:

• Trembling or freezing with or without tremors
• Constant pacing and restlessness
• Lip licking and hypersalivation
• Persistent hypervigilance
• Avoidance of eye contact
• Inability to eat or perform any behavior during a PTSD episode
• Reluctance or inability to engage in previously enjoyable activities
• Decreased performance in working dogs or rushing back to their kennels
• Hiding behavior
• Weight loss; chronic or intermittent diarrhea
• Deterioration in skin and coat quality
• Social withdrawal
• General loss of joy and decreased interest
• Self-injurious or destructive behaviors
  

When panic attacks accompany PTSD, mydriasis (pupil dilation), tachycardia, tachypnea, trembling, excessive salivation, diarrhea, vomiting, and aggression may be observed, along with an increased predisposition to other diseases.

Dr. Lori Teller, Associate Professor at the Texas A&M College of Veterinary Medicine and Biomedical Sciences, states:

“The symptoms of PTSD in dogs are similar to those in humans and may include chronic anxiety, hypervigilance, avoidance of specific people, places, or situations, sleep disturbances, decreased interest in favored activities, or aggression.”

Dr. Teller also notes that these signs may not be apparent at the time of adoption, as some dogs may mask their symptoms as a survival mechanism until they gradually adapt to their new environment, depending on their specific triggers.

Etiology and Pathogenesis

Individual susceptibility is not a prerequisite for the development of PTSD. The animal has objectively experienced a traumatic event. Such traumas may include:

• Electric shock from an electronic collar
• Change of owner
• Physical and psychological abuse
• Motor vehicle accidents
• Painful medical procedures performed without anesthesia
• Attacks by humans or other animals
• Abandonment and subsequent life on the streets
  

However, as an animal’s predisposition to fear increases, the likelihood of exhibiting a more severe response to trauma also rises.

Epidemiology

PTSD can develop in any dog; however, certain individuals are more predisposed. Puppies and animals exposed to abuse or neglect are at higher risk.

Trauma-Related Pathological Conditions

The effects of trauma may vary depending on the associated pathological condition:

Phobic Condition

In this condition, the animal reacts only to a specific stimulus that caused the trauma. For example:

• A dog involved in a car accident may develop fear toward vehicles.
• A dog that experienced a painful veterinary procedure may avoid approaching veterinary clinics.
• A dog attacked by a large black dog may develop fear specifically toward large black dogs or, more generally, toward all dogs.
• A dog beaten with a stick by a person may show a phobic response toward people walking or individuals with physical characteristics similar to the aggressor.

Anxiety Condition

In anxiety-related states, the animal anticipates the possible reoccurrence of the traumatic stimulus and therefore remains in a constant state of alertness. This may cause the dog to exhibit excessive vigilance even at home. Owners often cannot clearly explain why their dogs react in this manner but emphasize that such behavior was not present prior to the trauma. For example, a dog attacked by another dog may startle at any sound within an apartment building.

Trauma-Associated Depressive Condition

This condition typically begins as acute depression and may sometimes progress to chronic depression. The animal may exhibit learned helplessness and reduce interaction with its environment. For example:

• A dog subjected to electric collar shocks may refuse to leave the house.
• Post-traumatic anorexia may occur.
• The dog may completely lose interest in play.
  

Each of these conditions provides important insights into the emotional and behavioral changes that develop following trauma.

Comorbid Conditions Associated with PTSD

PTSD may occur concurrently with other behavioral disorders, such as:

• Separation anxiety
• Generalized anxiety disorder
• Compulsive behaviors
• Excessive barking or aggression

Factors Affecting the Severity of PTSD

The severity of post-traumatic stress disorder varies depending on the animal’s pathological condition. The nature and intensity of the trauma are major determinants of disorder severity. Additionally, the age at which the trauma occurs is a critical factor. An adult dog with previously well-adapted behavioral development may show recovery despite retaining traumatic memories. In contrast, trauma experienced at a young age often results in permanent damage and is more difficult to resolve.

Diagnosis

When diagnosing PTSD, the relationship between the traumatic event and the onset of clinical signs must be clearly established. The veterinarian can reach a diagnosis through clinical observation, information obtained from the owner, and behavioral assessments.

This blog post has been approved by Specialist Veterinarian Gökhan Durukan.

Resources :

Denenberg, S. (2020). Small Animal Veterinary Psychiatry. Severn, Alexandra Lainsbury.

Masson, S., Bleuer-Elsner, S., Muller, G., & Médam, T. (2023). Veterinary Psychiatry of the Dog: Diagnosis and Treatment of Behavioral Disorders. Springer.

Overall, K. L. (2013). Manual of Clinical Behavioral Medicine for Dogs and Cats. Elsevier.

Texas A&M Üniversitesi, Veterinerlik ve Biyomedikal Bilimler Fakültesi, “Caring for a Dog with PTSD”.