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Think Your Dog Is Having Nightmares? Here’s What You Need to Know.

Dogs exhibiting extreme behaviors during deep sleep — such as screaming and thrashing around — could actually be suffering from an REM sleep disorder.

Dog Having Nightmares
When I was just starting out as a veterinarian years ago, my friend said her dog was having nightmares. The dog was exhibiting what I would now recognize as classic signs of REM sleep disorder. Photo: vivros62

Dogs definitely dream. Most people have observed their dog twitching, doing a tiny paddling motion or quietly vocalizing during sleep. This is common.

Some dogs, however, have true sleep disturbances and exhibit extreme behaviors during deep sleep — such as growling, screaming as if in pain and even exhibiting aggressive behavior.

Veterinary behaviorists and neurologists believe these dogs suffer from a true sleep disturbance that occurs during REM sleep. Most people who observe these terrifying sleep disorders naturally think their dog is having a nightmare, a night terror or even a seizure.

If these episodes occur only during sleep, if you can usually wake the dog up with strong voice commands, and if the dog is neurologically normal during waking hours, then this is not a seizure disorder.

Veterinarians don’t classify these as nightmares or seizures but as an REM sleep disorder.

Dog having nightmares
If your dog seems to be having nightmares, record a video of the behavior to share with your vet. Photo: Pexels

What to Do If Your Dog Is Having “Nightmares”

If you observe frightening behavior in your dog during sleep, here’s what to do first:

  • Try to wake the dog up with your voice. Don’t touch or shake the dog. You could get bitten.
  • Take a video of the sleep disorder to show your vet.
  • If these episodes are particularly violent, a crate, even a padded crate, is a temporary safeguard.
  • Be keenly observant of your dog’s behavior while sleeping and awake. Take videos of anything you think is out of the ordinary.
  • Make an appointment with your vet to discuss the problem, show the videos, and rule out any medical problems that may explain the behavior.
  • Be prepared to consult with veterinary specialists if recommended by your vet.

A Terrifying Experience

As a veterinarian, I usually hear the same thing anytime someone comes in to see me with their dog after observing an intense sleep disorder episode: “It freaked me out!”

While sleeping, these dogs can:

  • Scream as if in intense pain
  • Exhibit episodes of violent limb movements
  • Run throughout the house
  • Howl, bark, growl or chew
  • Exhibit biting behavior to themselves or others
  • Chase or “pin” humans or other animals

The intensity and frequency of the episodes varies a lot from dog to dog.

Dog has nightmares
REM sleep disorder occurs most often in younger dogs — puppies up to 1 year old. Photo: Azoreskid14

Dog Nightmares: What We Know and Don’t Know

Veterinary neurologists believe these episodes are rapid eye movement (REM) sleep disorders.

REM sleep disorders occur in people and have been extensively studied. This is a harder disorder to study in dogs, but some research has been conducted.

The big difference between people and dogs is that people often develop this syndrome as they get older. But in dogs, REM sleep disorder often occurs in young dogs, which can be very troubling for the people caring for these puppies.

In one of the few studies conducted, 64% of sleep disorder dogs were 1 year old or less.

The exact causes of REM sleep behavior disorders is unknown. In humans, REM sleep disorders often occur later in life and can precede degenerative neurologic diseases such as Parkinson’s disease. It seems to be a different phenomenon in dogs since the average age of onset is so young.

Studies suggest possible causes of sleep disorders in dogs may include:

  • Congenital: In other words, the puppy was born with it.
  • Neoplastic: Cancer that affects the brain or neurological system.
  • Infectious: A primary brain infection or any infection in the body that crosses the “blood–brain barrier” and infects the brain. This could be bacterial, viral or fungal.
  • Degenerative: Meaning a degenerative brain disorder that leads to decreased brain function, like Parkinson’s in people. Dementia and senility would be in this category as well.
  • Idiopathic: Meaning it’s not traceable to a direct cause.
  • Vascular: A disruption in normal blood flow to the brain, similar to a stroke or transient ischemic attack (TIA, or ministroke) in people.
  • Traumatic: Head injury, for example.

Diagnosis of REM Sleep Disorder

Diagnosing REM sleep disorder in a dog is not easy.

  • An electroencephalogram (EEG) can demonstrate that the sleep-associated episodes occur during REM sleep, supporting a diagnosis of an REM behavior disorder.
  • Other brain imaging is necessary to rule out primary brain changes.

All of these tests require referral to a veterinary neurologist.

Vets usually diagnose REM sleep disorders using these tools:

  • Perform a thorough neurologic exam and get basic blood work, which should be normal.
  • Get a detailed history and videos from the pet parent. As I said earlier, if the pet is neurologically and behaviorally normal in every other way except while sleeping, it is most likely an REM sleep disorder.
  • Refer to a veterinary neurologist and/or behaviorist if the case is confusing or severe. Some people are not sure if their pet is normal while awake or may think they have observed seizure-like activity as well as the sleep disorder.

Dual Diagnosis

Seizure disorders and behavioral problems are fairly common in dogs. So it’s possible that a dog could have multiple things going on, making a diagnosis of REM sleep disorder more complicated.

Several case reports of dual diagnoses exist. After thorough neurologic and behavioral work-ups, pups have been diagnosed with REM sleep disorders as well as a seizure disorder, behavioral problems, obsessive-compulsive disorder, etc.

Most experts do not believe there is a correlation between REM sleep disorders and other neurologic or behavioral disorders, but more studies need to be done.

REM sleep disorder in dogs
A dog suffering from an REM sleep disorder might move their legs violently during deep sleep. Photo: PAWSS

Treatment of REM Sleep Disorder

Remember that this disorder varies greatly from dog to dog. Treatment depends on the severity of the condition and how the dog’s person is dealing with the problem.

Mild Episodes

If the episodes of the sleep disturbance are infrequent, not very intense or severe, not threatening to humans or other animals, and not disturbing the peace of the household, many people elect to have the dog sleep in a comfortable crate, padded if necessary, or a secure sleeping space.

Mild episodes themselves are not dangerous to the pet, so conservative treatment is an acceptable option.

Severe Episodes

More severe cases usually require drug therapy. Severity means:

  • Episodes occur nightly or multiple times a night.
  • The episodes are intense or intensifying with time.
  • The dog harms itself or others during episodes.
  • The dog cannot be contained in the environment.

Drugs that have proved most effective in treating REM sleep disorders in dogs include:

Dogs, like humans, can develop a tolerance to benzodiazepines, so many vets reach for potassium bromide first.

The response to drug therapy varies, just like the disorder:

  • Some dogs have their sleep disturbances completely controlled.
  • Others still have episodes, but they are less intense or less frequent.
  • Rarely is there no improvement at all.

If a combination of drugs does not relieve symptoms, it’s time to look further for an answer. There may be an underlying brain lesion.

Selective serotonin reuptake inhibitors (SSRIs) have been tried and may work in some cases — but some dogs actually get worse on an SSRI. This is true in people as well.

REM sleep disorder in a puppy
If you are concerned because your dog seems to be having nightmares, have your phone at the ready to record a video to show your vet. Photo: YvonneHuijbens

My First Case of REM Sleep Disorder

A friend’s dog was “having nightmares” — exhibiting what I would now recognize as classic signs of REM sleep disorder. This was in 1990, when very little was known about sleep disorders in dogs.

Chica was a middle-aged rescue dog with an unknown history. Shortly after adopting her, my friend said the dog was having nightmares frequently.

I remember telling her that things should get better once Chica felt more secure in her new happy environment.

But things got worse.

There were no cellphones back then, so recording these episodes was not as easy as it is today.

My friend thought I wasn’t taking the situation seriously enough, and I must admit I probably wasn’t. Once she explained how violent the episodes were and that this normally calm and peaceful dog was trying to bite her and was thrashing around in the middle of the night, I referred her to Cummings School of Veterinary Medicine at Tufts University, where she got some answers.

I remember this episode to this day, and it taught me a few lessons as a young veterinarian that helped me in my long career:

  • First, vets should take pet parents seriously. We shouldn’t dismiss a complaint that sounds a little wacky. People know their animals and usually know that something is really wrong, even if they can’t totally describe or explain it.
  • Second, vets should always be treating with humility, remembering that there’s still a lot to be discovered. We know more today than we knew 30 years ago. And we’ll know a lot more 30 years from now than we know today. So I try to keep an open mind and listen acutely to my clients’ concerns. That usually means we are starting out on the right foot so we can get the pet the help they need sooner rather than later.

If you are concerned because your dog seems to be having nightmares, have your phone at the ready to record. Or consider a nanny cam if your dog doesn’t always wake you up.

In these cases, a video is worth a thousand words.


  • Coren, Stanley, PhD, DSc, FRSC. “Do Dogs Dream?” Psychology Today. Oct. 28, 2010.
  • Bush, William, VMD, DACVIM, et al. “Diagnosis of Rapid Eye Movement Sleep Disorder With Electroencephalography and Treatment With Tricyclic Antidepressants in a Dog.” Journal of the American Animal Hospital Association 40, no. 6 (November–December 2004): 495–500.
  • Calder, Christine D., DVM, DACVB. “A Case Report: REM Sleep Behavior Disorder in a Jack Russell Terrier.” American College of Veterinary Behaviorists Veterinary Behavior Symposium, 2017.
  • Overall, Karen, VMD, PhD, DACVB, CAAB. Manual of Clinical Behavioral Medicine for Dogs and Cats. Elsevier. 2013.
vet-cross60pThis pet health content was written by a veterinarian, Dr. Debora Lichtenberg, VMD. This article was originally published in 2013 and is regularly updated. It was last reviewed for accuracy and updated Sept. 17, 2019.

If you have questions or concerns, call your vet, who is best equipped to ensure the health and well-being of your pet. This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. See additional information.