Obsessive-compulsive disorder affects about 2 million Americans, according to the National Institute of Mental Health. OCD is a distressing and often disabling condition characterized by overwhelming anxiety that drives the need to check things repeatedly or to perform certain rituals over and over. OCD is generally treated with psychotherapy, medication or both.
“Unfortunately, many patients often struggle with the decision of which treatment options to pursue,” says Dr. Francine Rosenberg, clinical psychologist and OCD specialist with The Morris Psychological Group in Parsippany, N.J. A new study published online in April 2013 in the journal Progress in Neuro-Psychopharmacology & Biological Psychiatry has the potential to open avenues to new understanding and treatment of OCD in people. It’s been known for some time that dogs with canine compulsive disorder exhibit similar behaviors to people with OCD. This research shows that changes in the dogs’ brains are also similar to those found in the brains of people with OCD. Researchers will be able to use this finding to advance our understanding of the biological mechanisms of the disorder and help people find relief.
Understanding OCD
OCD is a psychological disorder characterized by the presence of obsessions or fears that raise a person’s anxiety often paired with compulsions or rituals that decrease the anxiety. One familiar example is an obsession with germs that becomes a compulsion to wash one’s hands over and over or in a certain manner. Other compulsions associated with OCD include counting, checking, repeating, rereading or rewriting, tapping or touching things, putting things in a certain order and collecting worthless objects.
“We all have routines and rituals,” says Dr. Rosenberg. “We check to see that the door is locked, that the stove is off or that the alarm clock is set. But people with OCD do these things so often and obsessively that it disrupts their lives. And performing the ritual provides only temporary relief from the anxiety that triggers the behavior.” Psychotherapy, with or without medication, is often an effective treatment for OCD, particularly cognitive behavioral therapy, a short-term, structured approach that focuses on the dysfunctional thoughts and behaviors.
OCD is a complex illness whose exact cause is not fully understood. “There are biological, psychological and environmental factors in play in causing OCD,” says Dr. Rosenberg. “It sometimes runs in families, and some researchers believe about half the risk of developing OCD is genetically determined. But families also affect behavior in ways entirely unrelated to genes.” For example, how we cope with stress is often learned within the family. What is known is that MRI scans reveal changes in the brain common to people with OCD, particularly in the volume and density of gray matter in certain regions. In the canine study, veterinary researchers from Tufts University found structural abnormalities in the brains of a group of Doberman pinschers with canine compulsive disorder that were entirely consistent with those seen in people with OCD.
Dogs with canine compulsive disorder engage in repetitive and troublesome behaviors such as chasing their tails, sucking their flanks or a blanket, licking or nibbling their paws excessively, and even compulsively gathering objects very much like the hoarding sometimes seen in people with OCD. Doberman pinschers were studied because they are particularly susceptible to canine compulsive disorder– about 28% of Dobermans in the U.S. suffer from it — and because a genetic basis for the disorder has been established in the breed. Scientists had previously known that dogs suffered from a canine equivalent of OCD, that they often responded to the same medications as people, and that both disorders appeared to have a genetic basis. The new findings add an additional similarity – that structural brain abnormalities are the same as well – adding to the body of knowledge of how biology, genes and environmental factors interact to cause behavior problems.
We can learn a great deal about anxiety disorders from studying animals. We now know quite a lot about the similarities between OCD and canine compulsive disorder. Anything we can identify about the underlying mechanisms of obsessive-compulsive disorder will put us in a better position to develop more effective treatments.
