Thursday, 29 March 2012

Compulsive Behaviours in Dogs: Not as lolz as YouTube thinks.


This is Oliver.


He’s pretty cute, right? (Right.)

Unfortunately, Oliver spent the first few months of his life wandering the streets, going from shelter to shelter, and generally having a rough time. As a consequence of these highly stressful formative experiences, Oliver developed a compulsive disorder, which manifested as serious tail chasing. Like, seriously bad tail chasing. Poor guy would tear out the hair and chew on his tail until it was raw and bleeding. Not pleasant. What’s interesting, though, is that while lots of dogs have stressful early experiences, not all of them develop these compulsive behaviours.

Though the video is titled ‘funny dog chases tail’, this condition is actually the start of something pretty serious, behaviourally speaking.

Recent scientific advances have shown that there are certain genes that are far more common in dogs that develop Canine Compulsive Disorder (CCD) than those who do not, which indicates that some animals have a genetic predisposition to respond to anxiety, frustration or stress in this way. There are several recognised manifestations of CCD, including tail-chasing, pacing, and over-grooming. A specific kind of over grooming is called ‘flank-sucking’, and is particularly common among Doberman Pinschers. Flank-sucking is pretty much what it sounds like: the dog compulsively licks, bites and sucks on its hind quarters and back until the area becomes irritated, and in many cases develops dermatitis and infection. Another common affliction for Dobies is blanket-sucking, which can lead to ingestion of massive amounts of fabric,  causing choking and blocked digestive tracts.

You can see in this clip the fervour with which this little guy is grooming himself. This is not a response to an itch or bite, but a compulsive behaviour.

The research is a joint effort of Tufts University and the Broad Institute at MIT, and outlines lots of complicated things about how they identified this gene that looks to be responsible for CCD. Essentially, they mapped the genome of a bunch of Doberman Pinschers, both those affected by CCD and not, It pretty quickly became apparent that one gene, CDH2, was appearing commonly in dogs with CCD, and rarely in those without it. (About 60% of the time in those dogs with serious CCD, and only about 20% of the time in those without the disorder.)

This discovery has implications for medical as well as veterinary science. It is estimated that anywhere up to 8% of the human population suffers from Obsessive Compulsive Disorder (OCD). This disorder manifests in similar ways as CCD, including hair pulling and pacing, and also in activities such as excessive hand-washing or counting of objects.

Scientists who were not directly involved in the study are examining the CDH2 gene in humans, and investigating any links it might have with OCD. Further results of this type of research will hopefully lead to the development of drugs that can target this gene, and allow both animal and human sufferers of compulsive disorders to return to a normal life.

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