Narcolepsy in Horses – Did You Know?

By Karen Carlson

The other day I was having lunch with a friend, and she mentioned that a gal she knows has a horse that may have narcolepsy. It caught my breath. I had never considered that this disorder may occur in the equine species.

Horses sleep so little each day that I would never imagine narcolepsy would happen for them. Horses rest a lot. In fact, most of every day is eating or resting, but actual sleep is not part of their nature.

Adult horses sleep about three hours in a 24-hour period, with younger horses and senior-aged horses sleeping more than that, just as in the human species.

I asked what would make anyone think a horse may have narcolepsy. She explained that it is not yet confirmed, but the horse is suddenly unable to travel because she passes out in the trailer. This is a horse that has been to many shows, won too many ribbons and prizes for me to mention, and has been in a trailer to travel all over the state for several years.

My friend explained that the vet the owner is consulting about this horse is performing some tests and gathering more information, but the thought is narcolepsy at this time.

Narcolepsy is a sleep disorder involving the brain. It occurs when the brain cannot normally regulate cycles of sleep and wake. This can cause daytime excessive sleepiness that results in episodes of falling asleep suddenly, according to the National Institute of Neurological Disorders and Stroke (NINDS).

In addition to excessive sleepiness, many patients with narcolepsy experience sudden loss of muscle tone (called cataplexy). This often occurs in the knees, face and neck, and may be triggered by emotions like excitement or surprise.

This diagnosis does make sense for this particular horse because, when she is placed in a trailer and it begins to move, she passes out and falls over. The cataplexy hits the horse hard. This situation has frightened the owner of the horse, who also didn’t consider narcolepsy as a potential problem at the onset.

The first episode made the poor owner think her horse had dropped dead. How scary for her! Narcolepsy is not a result of lack of sleep but does cause excessive tiredness, as noted by the NINDS.

After doing some research on the subject, and let me remind you that I am not a veterinarian, I found that just as in people, the cause of  equine narcolepsy is not fully known. It is believed that sometimes the body’s immune system mistakenly attacks the brain cells involved in regulating the sleep cycle and that narcolepsy may be the result of these cells being damaged or destroyed.

It has been found that some horses are born with the condition and may recover, some will live with it forever, some have adult onset and sometimes it is stress induced.

I also found that it is more common than I would have imagined. It just goes undiagnosed in milder cases much of the time. We’ve probably all known a horse with the disorder but never suspected it.

I’ve seen horses pass out at the hitch rail, even fall over, but it never crossed my mind that this was an issue of narcolepsy. I’ve seen horses pass out, or nearly so, upon being cinched. That, too, may be a form of the condition.

Treatments are available. Imipramine is a tricyclic antidepressant but has had inconsistent results. Another treatment, Atropine sulfate, relieves the condition in horses for up to 30 hours. Both of these drugs have been reported to cause colic attacks, so the risk may far outweigh the benefit. If you think your horse may have narcolepsy, talk to your vet.

While narcolepsy is not deadly, the result of falling, passing out and hitting things or getting stuck and thrashing about certainly can be deadly. With or without drug therapy, narcoleptic horses require more monitoring, thought and attention to their environment than normal horses.

Talk to your vet, friends, and conduct your own research to keep your equine friend as safe as you can. If you suspect you’ve got a sleeper on your hands, it just may be true. Books and online information are available, and to know that you are not alone provides a bit of comfort.

I continue to learn and be amazed that these giant creatures that seem so robust and durable are actually quite delicate and sophisticated. I am hoping that this may help any of you who have a horse with possible symptoms of narcolepsy to figure out that it indeed could be just that.  I’ll bet I’m not the only one who woulda never thunk it!

Karen Carlson, a Ramona resident, is past president of Ramona Trails Association and a trails advocate. For questions or comments, contact Karen and Cricket at

Related posts:

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  2. Manes and Trails: Rattlesnakes and your horses
  3. FalconRidge Equine Rescue: A sanctuary for unwanted, abused, and neglected horses
  4. Manes & Trails: Equine colic
  5. Manes & Trails: Equine travel and illness

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Posted by Karen Brainard on Apr 20 2014. Filed under Columnists, Columns, Manes and Trails. You can follow any responses to this entry through the RSS 2.0. You can skip to the end and leave a response. Pinging is currently not allowed.

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