Repetitive abnormal behaviors performed out of context have been described in various species of farm and zoo animals (7). When exhibited by companion animals, these abnormalities are usually referred to as obsessive-compulsive disorder (OCD) or compulsive disorder (CD) because of the similarities with human OCD (4,11).

The behaviors performed by dogs with CD can be categorized as locomotory, oral, vocalization, aggression, and hallucinatory behaviors (7). Locomotory behavior includes circling, tail chasing, pacing, jumping in place, chasing light reflections, and freezing behaviors. Aggression can be displayed as self-directed aggression led to self-injury behavior. Oral behavior includes leg or foot chewing, self-licking, air or nose licking, flank sucking, scratching, chewing or licking of objects, polyphagia, polydipsia, pica, and fly snapping.

The patient in this case report had shown certain behaviors related to aggression that are generally indicative of CD in dogs, including self-directed aggression (growling or biting the rear end, rear legs, or tail), attacking their food bowl or other inanimate objects, and possibly unpredictable aggression towards people.

CD is sometimes associated with structural abnormalities. Dogs with CD exhibit higher total brain and gray matter volumes and lower dorsal anterior cingulate cortex and right anterior insula gray matter densities. Dogs with CD also have higher fractional anisotropy in the splenium of the corpus callosum, the degree of which is correlated with the severity of the behavioral phenotype (10).

CD may be related to breed, although various breeds show such behaviors. For example, tail chasing is most commonly observed in Bull Terriers and German Shepherd Dogs (1,8,9).

According to previous studies, CD constitutes 13.2% of all surveyed other behavioral problems (2). It is therefore considered to be one of the most important behavioral problems (6,13).

There have been various trials to treat and manage CD behaviors (14): Pharmacologic strategies using serotonergic drugs (clomipramine, fluoxetine) or MAO-B inhibitors, or NMDA receptor antagonists; Environmental modification; using protective tools, and behavior modification (16). Clomipramine and fluoxetine seem to be equally effective in the treatment of tail chasing, for example, dogs in one trial responded well to each treatment and there was no significant difference between the effects of the two drugs (16).

A nine-year-old castrated male miniature poodle was presented the clinic for treatment of a tail injury caused by self-traumatic behavior. The dog had been treated surgically for self-inflicted tail wounds at other clinics several times throughout his life. Some family members had considered his euthanasia because of this behavioral problem along with aggressiveness toward people in certain stressful situations. After the injury had healed completely, he still paid excessive attention to the back of his body and showed stress-related behaviors, including frequent backwards glances, growling toward the back of his body, and biting and chewing his tail. Treatment of the self-traumatic behavior through behavioral consultation or medication was considered.

At the first visit to the clinic, the end part of his tail was severely desquamated by concentrated self-licking, chewing, and biting (Fig. 1). He frequently tried to look back and bite his tail wound. It was necessary to confirm whether this behavior was due to the stimulus of the injury or behavioral problems. The wounded part of the tail was sheared, washed daily with sterilized saline solution, and disinfected; in addition, he was treated with oral medication for ten days including cephalexin (Falexin cap.; Donghwa phar.) 22 mg/kg and famotidine (famotidine tab.; Hanmi) 0.5 mg/kg twice daily (12). The injury was also protected by a bandage and Elizabethan-collar for the duration of the healing period. After ten days, the injury was fully healed, however, the problematic behaviors continued.

Figure 1. The tail wound by self-traumatic behavior of the case.

For the behavioral consult, a basic physical examination was performed. His weight was 8.5 kg with a normal body shape for a body condition score (BCS) of 6/9. He had not been treated for any disease except the recurrent tail injuries. No typical sign of any skin disease was found. He had mild Otitis Externa., so it had been treated by regular ear cleansing only. (without any special medication prescription) The pruritus inducing diseases like atopic dermatitis were not found. We conducted the basic neurological examination during physical examination including gait monitoring, facial and eye reflex assessment and spinal and joint palpation. There was no remarkable finding. He had normal joint status, including the stifles and pelvis, and no significant pain reaction was found, even at the back side. Blood test results, including complete blood cell count (CBC) and serum chemistry, showed no remarkable findings.

The dog was adopted from a pet shop at two months old tail-docked. Castration was done at six months old. Management of his nails and ears was difficult because of aggression, including sudden biting and growling, especially when the hind part of the body was touched. He also showed aggression at veterinary consultations. Several biting incidents directed towards strangers had occurred, although the owners had strictly monitored this situation. He showed sensitive responses, including barking at other people or dogs met outside of the home. The most important behavioral issue, however, was tail mutilation.

The dog was diagnosed with CD with tail mutilation, along with aggression. Pharmacological treatment was deemed necessary to treat these problems.

In the first week, fluoxetine (Proctin cap.; Myungin phar.) 2 mg/kg once daily, trazodone HCL (trazodone 25 mg tab.; Myungin phar.) 5 mg/kg twice daily, and gabapentin (gabapentin cap.; Donga phar.) 50 mg/kg twice daily were prescribed (12). Since there was a significant loss of appetite and vitality, the prescriptions were adjusted to fluoxetine 1.5 mg/kg once daily, trazodone 3 mg/kg twice daily, and gabapentin 30 mg/kg twice daily from the second week. Tail biting behavior ceased within two weeks of drug administration, but the dog continued to check his tail. In addition, the dog’s sensitivity to basic care, including nail clipping and ear cleaning, was significantly reduced at each visit. Within a month of administration, it was possible to proceed with care without restraining equipment, such as a basket-type muzzle. After consistent administration for more than six months, the drug dosages were reduced to fluoxetine 1 mg/kg, trazodone 3 mg/kg, and gabapentin 30 mg/kg once daily; tail biting did not recur. When the owner arbitrarily reduced the drug administration to once every two to three days, they observed that the dog intermittently paid increased attention to his tail. When the drugs were administered daily again, this behavior was significantly reduced.

After pharmacological therapy, the patient’s quality of life was greatly improved and the owners were very satisfied with treatment outcome. For this reason, the prognosis was deemed positive. Annual bloodwork may be required because of the dog’s age.

As in humans, dog behavior can be affected by environmental stress and poor caretaking attitudes, as well as anatomical and physiological abnormalities. Genetics can also be an important factor, for example, one study showed that tail biting and spinning can be influenced by genetics in Bull Terriers, German Shepherds, and other breeds (9). The patient in this case was treated with medication as he was diagnosed with self-directed traumatic behavior, and the behavioral concerns ceased within two months.

The differential diagnosis has to consider various behavioral, neurologic, dermatologic, and other medical conditions (7). The physical examination including dermatological, neurological assessment showed the dog’s behavior was due to the behavioral problem: CD.

Medications affiliated with SSRI drugs, such as fluoxetine, are known to be helpful in alleviating such compulsive behaviors (15). Fluoxetine is a serotonin selective reuptake inhibitor (SSRI) that is widely used to treat OCD in humans, and is recommended by veterinary behaviorists to treat CD in dogs (5,15,16). For example, owner-reported severity of CD in one study was more likely to decrease compared with the baseline severity in dogs treated with fluoxetine than in dogs treated with a placebo (5). Adverse effects, like lethargy, appetite changes, and gastrointestinal disturbances, were generally mild and self-limiting (5,15). Although trazodone has an extensive history of use in humans, few clinical data are available on the use of this drug in dogs (16). Trazodone as an adjunctive agent is needed to enhance pharmacologic treatment of dogs with anxiety disorders who are insufficiently responsive to conventional treatment protocols, as well as dogs initially responsive to treatment who relapse over time (3).

In this case, trazodone was prescribed to as an adjunctive medication to fluoxetine, the slow-onset drug. Fluoxetine is long-term acting anti-depression drug. For owners, it is very easy to be misunderstood the medical treatment is not useful. So, fast acting anti-depression drug like trazodone was added to accelerate the effects. For the reason, this drug combination may produce positive compliance of owners on this kind of long-term treatment. In addition, gabapentin was also prescribed for unevaluated pain or discomfort, and the prescriptions were effective. With the exception of a mild loss of appetite, there was no observation of side effects caused by the drugs, such as vomiting or diarrhea. There were also no abnormal changes detected by CBC and serum chemistry.

In this case study, the patient’s CD was greatly improved with psychotropic medications. It is ideal to refer a patient with behavior issues to a veterinary behaviorist. However, if veterinary behaviorists are not accessible, starting psychotropic drug treatment will be the first step to helping the patient’s physical and behavioral health.

The authors have no conflicting interests.