Researchers have identified genetic pathways exacerbating the severity of canine compulsive disorder (CCD), which could lead to better therapies for obsessive-compulsive disorder (OCD) In humans.
Scientists behind the study, which was published in the February edition of the International Journal of Applied Research in Veterinary Medicine, hope it will expand therapy options and, ultimately, bring relief to those suffering the most.
“Dogs naturally suffer complex diseases, including mental disorders that are similar to those in humans. Among those is CCD, the counterpart to human OCD,” explains the study’s first author, veterinary behaviourist Nicholas Dodman.
Listed among the 20 most disabling diseases by the World Health Organization (WHO), OCD is often characterised by distressing thoughts and time-consuming, repetitive behaviours. Canine compulsions include repetitive tail chasing, excessive grooming, and flank and blanket sucking.
The study shows current OCD therapies are not as effective as they could be, as medicinal treatment only benefits around half of human patients. No previously recorded study in humans or dogs has addressed the factors driving severity in OCD and CCD.
Neurologist Edward Ginns, co-author of the study, said: “CCD shares behavioural hallmarks, pharmacological responsiveness and brain structural homology with human OCD, and thus is expected to be an important animal model.”
The research team compared whole genome sequencing of 70 Dobermann pinschers to search for inherited factors that exacerbate CCD.
Researchers identified two loci on chromosomes strongly correlated with severe CCD, as well as a third locus showing evidence of association. The locus most strongly associated with severe CCD was found on chromosome 34 – a region containing three serotonin receptor genes.
Prof Dodman said: “This is particularly significant because drugs that work on the serotonin system are the mainstay treatment for OCD in humans, which demonstrates further correlation between the human and animal models.”
MRI research conducted in 2013 from the Cummings School of Veterinary Medicine at Tufts University and McLean Imaging Center at McLean Hospital showed the structural brain abnormalities of Dobermann pinschers afflicted with CCD were similar to those of humans with OCD.
Prof Dodman said: “If the canine construct is fully accepted by other OCD researchers, this spontaneously-occurring model of the condition in humans, right down to the biological pathways involved, could help point the way to novel and more effective treatments for such a debilitating condition.”
For further details, read Genomic Risk for Severe Canine Compulsive Disorder, a Dog Model of Human OCD