Dogs put a bite on obsessive compulsive disorder

Man's best friend has made a contribution to science that could help lick obsessive compulsive disorder in humans. An analysis of dogs with the disorder has identified four genes that are strongly linked to the condition, and similar genes may be involved in the human version of OCD.

OCD affects up to 3 per cent of humans, and certain dog breeds are also more susceptible to OCD than others, according to scientists from the US and Sweden. While humans with the condition might compulsively wash their hands or repeatedly check things, canine symptoms include repeated grooming, constantly chasing their own tails or sucking on a blanket.

Dog breeds particularly susceptible include Doberman pinschers, bull terriers, Shetland sheepdogs and German shepherds.

Mouse models are often used to study OCD, but the mouse must be genetically altered to make it have the condition. The authors from the Broad Institute in the US and Uppsala University decided that dogs might provide a better model given the disorder occurs in them naturally, as in humans. And the dog symptoms can be relieved if they are given certain antidepressant drugs, again as is the case with people.

“It is intriguing that the clinical presentation and treatment strategies for OCD are so similar between dogs and people,” said co-senior author Prof Kerstin Lindblad-Toh, professor at Uppsala University and Broad Institute, “We therefore designed our study to take advantage of comparisons between the behaviour in dogs and humans.”

The team began a comparative genome study looking for similar gene variations between the four breeds. They looked at eight dogs with the condition and eight without OCD and identified a number of gene variations that occurred in obsessive compulsive dogs but not in the healthy control dogs. They then looked at another 88 dogs with and without the condition and managed to find four specific gene variations or mutations that seem strongly linked to OCD, they write this morning in the online open access journal BioMed Central .

The work provided proof of concept that that dogs with the disorder could be a useful model for human OCD, the authors write. They said that much more work was needed to confirm whether the same mutated genes were also involved in the human form of OCD.

It does however give the researchers a head start in where to look for the responsible genes. It also makes it easier to trial drugs that might help eliminate the troubling symptoms of obsessive compulsive disorder.

See the research article from BioMed Central at: http://genomebiology.com/2014/15/2/R25