Dogs develop compulsive behaviors as well, just like humans, described as canine compulsive disorder (CCD). Researchers now say that studying CCD may be able to provide insight into OCD.
What's going on in the brains of dogs?
Most dog owners have probably seen their dog chasing its tail at least once. While this is a funny thing to witness, the situation gets less and less humorous as it happens more and more. Tail-chasing can become a compulsive behavior in dogs, along with obsessive licking, snapping, or hoarding. While these behaviors in themselves are harmless, they can turn into compulsive behaviors once the dog performs them excessively.
These compulsive behaviors can cause injury to the dog. Veterinarian Nicholas Dodman had been seeing dogs with CCD, including a bull terrier named Sputnik. Sputnik was a tail-chaser, spinning for hours on end, continuing even when he was already bloody. His owner has had to physically restrain him, and euthanasia became a possibility.
Excessive tail-chasing is a symptom of CCD.
Sputnik is now as normal as a dog can be, though one has to ask: in the recesses of his dog mind, does he still think about chasing his tail? Observing canine compulsive disorder has presented a new vantage point from which to examine obsessive-compulsive behavior in humans as well.
Judith Rapoport wrote The Boy Who Couldn't Stop Washing in 1989, a book that helped put OCD in the spotlight. It allowed people to understand the condition at least a little more, but it also prompted dog owners to write Rapoport and tell her that their dogs were displaying behaviors similar to OCD.
Rapaport then designed a double-blind placebo experiment for dogs with CCD. According to the findings, serotonin drugs were able to treat dogs displaying obsessive behaviors. Still, Rapaport says that diagnosing CCD isn't the same as diagnosing OCD. The biggest difference, of course, is that humans can talk—express that they want to stop doing something but are unable to—and dogs can't.
Serotonin may not be telling the complete story of obsessive-compulsive behaviors. Dodman's work showed that glutamate may play a key role as well. However, it may be prudent to take a look at how genes can also affect obsessive-compulsive behaviors in both dogs and humans.
Are dog and human minds more similar than we think?
Dodman worked with geneticist Ed Ginns to conduct a genome-wide analysis on 92 doberman pinschers displaying obsessive-compulsive behaviors. The findings indicated that a neural cahedrin called CDH2 may be worth looking at. CDH2 is involved with glutamate receptors in the brain.
In another study involving compulsive dobermans, Dodman found that the dogs' brains had structural abnormalities similar to those found in humans with OCD. Dodman's latest work on the subject, meanwhile, is another genome-wide analysis hat presented a dog model of understanding OCD in humans.
Accepting a model like this boils down to a philosophical thing, says Dodman. The real challenge, according to him, is accepting that dog and human minds may have more in common than previously thought. Given the similarities between obsessive-compulsive disorder in humans and canine compulsive disorder, this may not be much of a stretch.
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