June 01, 2008

 
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Odd behavior may be serious compulsive disorder

 
posted May 15, 2008
 

Some pet behaviors are strange but harmless. Others
may be a sign of a serious problem.


A popular YouTube clip features a dog growling and biting at a potential threat to its chew bone. The punch line is the threat is actually the dog's own hind limb. To the untrained eye, the clip is hilarious. Veterinary behaviorist Dr. Terry Marie Curtis sees it differently, however.

Dr. Curtis, in fact, believes the dog is suffering from an obsessive-compulsive disorder on par with the teenager who washes her hands so much they bleed or the adult who stays up through the night repeatedly locking and unlocking the front door.

"People laugh at that clip, but it makes me very sad to see the dog that upset and worried about itself," said Dr. Curtis, a diplomate of the American College of Veterinary Behaviorists who spoke about OCD in pets during a session at the American Animal Hospital Association annual meeting.

Animal OCD is a serious welfare issue. Pets suffering from the disorder can become ill because they neglect to eat or sleep. Self-mutilating pets might require medical treatment or surgery. Persistent behavioral problems may eventually drive a pet owner to relinquish the animal or opt for euthanasia.

Although OCD is a human psychiatric diagnosis, it does occur in animals, according to Dr. Curtis, who is director of Behavioral Services at the University of Florida Veterinary Medical Center.

An obsession, she explained, is a persistent thought or impulse that causes anxiety or distress. A compulsion is a repetitive behavior or mental act aimed at preventing or reducing distress. In animals, it's impossible to confirm the obsession. "The only compulsions we can be certain of are those that manifest as overt behaviors," Dr. Curtis said.

Compulsive behaviors in animals show themselves in a variety of strange ways. A cursory list includes tail chasing, pacing, excessive grooming, overeating, vocalization, self-directed aggression, staring, and hunting imaginary prey.

However an OCD manifests, the behavior defies easy explanation. Dr. Curtis showed video of her patient Ranger, a German Shepherd Dog that, after frantically digging holes in his owner's backyard, would suck on his paw and carry it around in his mouth as though it weren't attached.

There were no obvious reasons for Ranger's behavior, but something was driving the dog to act in such an odd way. Possible explanations for a pet's compulsive behavior are frustration or boredom; it could be over-stimulation or conflict with another animal; the owner might be unwittingly rewarding attention-seeking behavior; or the disorder may have a physiologic cause, such as brain lesions.

Genetics could also be to blame. Siamese, Burmese, and other Oriental cat breeds, for instance, are predisposed to wool sucking or fabric eating.

Diagnosing OCD requires a thorough behavioral history, Dr. Curtis said, along with observation of the behavior and ruling out of medical causes—a very important piece of the puzzle. Dr. Curtis recommends the referring veterinarian document the behavior, noting such details as how long the behavior lasts, past treatments, and whether the behavior can be interrupted.

It's also important to document the owner's response to the behavior, which can help pinpoint an attention-seeking component, she added.

Not every strange, repetitive behavior is necessarily a result of a compulsive disorder. Seizures or other treatable causes might be the culprit, Dr. Curtis said.

She recalled the case of a six-pound feline patient that was constantly eating nonfood items such as towels, pencils, and clothing. It turned out that the owner was feeding the cat just eight kibbles twice a day. Instead of having an OCD, the cat was anxious about the timing and small amount of food, and expressed its worry by eating whatever it could find, Dr. Curtis said.

The solution was to make small amounts of food readily available whenever the cat wanted. "I didn't want the cat to worry about food," she explained. "I didn't want anxiety building over 'Where is my next meal coming from?' So we gave the patient what it needed."

Other cases will require a combination of pharmacologic treatment and behavior modification. For Ranger the German Shepherd Dog, Dr. Curtis prescribed anti-anxiety medicine and instructed the owner not to let him run loose in the yard but to instead put him on a head collar and take him for a walk or run. And when Ranger was in the yard, the owner was to throw a ball or stick to keep the dog active, distracting it from obsessive behavior. Ranger's compulsion eventually ceased.

"That's one of the most important things you can do while the animal's on medication: change its behavior," Dr. Curtis said.

Dr. Curtis pointed out that behavioral medication involves highly structured interactions, and owner-administered punishment is to be avoided. Environmental changes, such as removing sources of conflict or distress, are also necessary.

While no medication used to treat OCD in animals has proved 100 percent effective in all patients, selective serotonin reuptake inhibitors and tricyclic antidepressants have had success, Dr. Curtis explained. In rare cases, narcotic antagonists and even antipsychotics/neuroleptics may be necessary.

For more information about obsessive compulsive disorders in animals, Dr. Curtis recommends "Blackwell's Five-Minute Veterinary Consult Clinical Companion–Canine & Feline Behavior" by Drs. Debra F. Horwitz & Jacqueline C. Neilson and "Clinical Behavioral Medicine for Small Animals" by Dr. Karen L. Overall.