Dogs may once again prove to be man's best friend, this time in new canine research findings that might help doctors get a better handle on obsessive-compulsive disorder (OCD) in humans.
Brain scans suggest that dogs who suffer from a comparably debilitating condition known as canine compulsive disorder (CCD) show similar structural brain abnormalities as those found in people diagnosed with OCD.
Alongside prior research that suggested OCD and CCD share the same genetic underpinnings, the same behaviors and the same responses to treatment, this latest study indicates that the disorder's biological progression among man's four-legged companions may offer valuable insight into a poorly understood human condition.
"This is an exciting finding because the current treatment options for OCD are less than satisfactory, with only about half of patients responding well, which means we need to develop new ones," said study co-author Nicholas Dodman, a veterinarian with the Cummings School of Veterinary Medicine at Tufts University in North Grafton, Mass. "So, one way to do that is by lifting up the hood on anxiety disorders among dogs. And by examining the mechanics of CCD, we hope to get a more complete picture of the physiology and anatomy of OCD."
Dodman, who is also the director of Tuft's Animal Behavior Program, and his team reported the findings online recently in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry.
The researchers pointed out that OCD strikes roughly 2 percent of the population, manifesting in a wide array of ways that can include continual hand washing or the uncontrollable hoarding of objects.
Although the physical and mental compulsion to engage in anxiety-relieving repetitive behaviors can be extremely detrimental to a patient's quality of life, many endure the disorder's relentless and intrusive stress for years before finally getting a proper diagnosis.
The International OCD Foundation estimates that, on average, OCD patients struggle with the disorder for 14 to 17 years before getting appropriate treatment.
Treatment typically involves selective serotonin reuptake inhibitors (SSRIs), which include well-known antidepressants such as Prozac, Paxil, Lexapro and Zoloft. Another option is cognitive behavioral therapy, which utilizes "exposure-and-response prevention" techniques, to acclimate patients to fearful stimulation and remove related anxieties.
The problem: a big swath do not seem to benefit from either approach; the OCD Foundation pegs that number at 30 percent of patients. What's more, among those taking medications, symptom reduction typically falls by only 40 percent to 60 percent, leaving many to continue to struggle with substantial compulsive behavior.
In the canine study, Dodman's team focused on 16 Doberman pinschers, a breed that appears to be particularly prone to developing CCD.
While half the dogs were healthy, the others had CCD. In dogs, Dodman explained, this can take the form of repetitive licking of their lower extremities; tail-chasing; irregular appetite; inappropriate nursing behaviors; or the compulsive gathering together of objects that mimics the kind of hoarding sometimes seen among OCD patients.
Using MRI scans and cutting-edge software, the team was able to map out detailed brain changes associated with CCD that were not seen among the healthy dogs. Differences included higher total brain and gray matter volume among the CCD dogs, as well as lower gray matter density in particular brain regions.
In turn, by comparing these abnormalities with those already seen in human OCD patients, Dodman said that even with the small sample size he and his colleagues determined the brain changes were "precisely identical."
However, Kiara Timpano, an assistant professor in the psychology department of the University of Miami, argued that the most effective approach to OCD treatment involves a combination of SSRI meds and cognitive therapy.
"We can even treat OCD with cognitive therapy alone," she added. "Pharmacological treatments are an option, but they don't necessarily need to be a component of therapy," Timpano explained.
"However, certainly medications are one of our treatment tools," she noted. "And obviously the more we can understand about the underlying mechanisms of OCD -- biological, cognitive or behavioral -- the better we will be able to develop more effective treatments, including medications. So, with respect to using an animal model such as this, I think it's great."