Compulsive disorders are characterized by repetitive or sustained behaviors performed out of context to the point that they seem abnormal.They are performed for excessive durations and can lead to physical injury. Moon-Fanelli observes that, “These behaviors are derivations of hard-wired behaviors necessary for survival, such as eating and grooming.” For instance, tail chasing or spinning, as well as cases where dogs chase lights or shadows, are forms of predatory behavior. Flank-sucking in Dobermans, during which the dog turns around and grabs and sucks on her flank, may be considered a form of eating or ingestive behavior. These dogs occasionally ingest blankets that their owners provide for them to suck on.Acral lick dermatitis, in which dogs spend hours licking the wrist area of their front legs, can be a form of over-grooming.
Unlike the repetitive spinning or pacing one might see in a zoo animal living in boring environments—those animals repeat the same movements over and over—with compulsive behaviors, it’s the goal that matters. That is, in some cases, compulsive spinners may spin in more than one direction, compulsive pacers wander around the house rather than in an unerring path, and light- or shadow-chasers follow the light or shadows rather than a particular footfall pattern. Some cases can be difficult to distinguish from stereotypes, but regardless of the form the compulsive disorder takes, the behaviors are virtually out of the animal’s control. Says Dodman, “It’s like a continuous loop circuit, and the behaviors are constantly recycling and repeated.”
Compulsive Disorder in Dogs vs. OCD in Humans
As suggested, compulsive disorders in animals are similar in appearance to obsessive-compulsive disorders (OCD) in humans; however, because animals cannot express their internal states in words,we don’t know whether they obsess. In humans, the behavior is driven by unreasonable obsessions.For instance, OCD sufferers may feel overly concerned for their safety or hygiene. The obsessions cause anxiety, which causes the sufferer to engage in compulsions in an attempt to alleviate the distress brought on by the obsession.Performing the compulsions, such as repeatedly checking that all of the doors are locked or repeatedly showering or hand-washing, provides relief. This relief is short-lived, though, and the compulsive symptoms actually worsen.
How does this differ in animals? According to Luescher, the same area of the brain may be affected in both dogs and people. People with OCD have changes in the prefrontal cortex of the brain, the area that animals use to reason or to interpret their environment. Luescher has performed brain-imaging studies on a Bull Terrier with compulsive fixation on objects and found that this dog’s prefrontal cortex was involved. According to Luescher, such findings don’t mean that the conditions are completely homologous; even if human OCD patients and canine compulsive disorder patients are physiologically similar, there is a difference. “People with OCD suffer partly because they know it does not make sense,” he states. “They feel ashamed and try to hide their symptoms. Dogs, on the other hand, perform their behaviors openly.” So they are not ashamed about the behavior; however, they may be anxious or distraught while they are performing the behavior.
Despite the differences, compulsive behaviors in humans and animals are related in that they are anxiety-based, and some animals carry a genetic predisposition. As Moon-Fanelli, whose research focuses on the inheritance of compulsive disorders in Bull Terriers, notes, “We think compulsive disorders are hereditary because we see some of these compulsive behaviors more frequently and almost exclusively in certain breeds.” For instance, German Shepherds, Australian Cattle Dogs and Bull Terriers spin or tail-chase; Wirehaired Terriers tend to shadow- or light-chase; and Dobermans flank-suck or blanketsuck. Additionally,Miniature Schnauzers compulsively check their rear ends. They may walk a few steps and then stop and look at their hind end, or get up and check the area where they were sitting or sniff it.