Owner-Directed Aggression in Dogs

Chevy the dog would snarl, growl, and bite to such a degree his owner considered euthanasia.


[From Tufts June 2012 Issue]

This is one in an occasional series by best-selling author Nicholas Dodman, BVMS, DACVB, director of the Animal Behavior Clinic at Cummings School.

Back in 2005 a troubled owner brought us her 5-month-old neutered male mixed breed dog, Chevy, for evaluation and treatment of owner-directed aggression. Specifically, Chevy had growled at and bitten his owner in various situations, all involving food or stolen objects.

Some people refer to this type of aggression as “possessive aggression,” which is often a component of what is now known as “conflict aggression.” Chevy had a few other issues too, and his owner reported that he was always nervous in the car, salivating and vomiting during car rides. He also chased and chewed his tail and exhibited coprophagia (eating his own excreta). Other than these issues, his owner euphemistically reported, he was a well-behaved dog.

Managing Dogs to Avoid Further Conflict

The initial treatment plan, which was outlined by one of my associates, was to take steps to avoid further conflict by: a) denying him access to things he might steal or want to protect and b) ignoring him if he grabbed a forbidden object despite his owner’s best efforts to keep such items from him. If, however, Chevy managed to steal something that was potentially dangerous — something he might swallow, for example — or something that was valuable to his owner, our instructions were to divert him rather than confront him in order to reduce ongoing conflict.

The other part of the treatment program was what is sometimes referred to as the “nothing-in-life-is-free” protocol, through which a dog has to earn things he takes for granted and either wants or needs. It was particularly important, we felt, to have Chevy working for food and treats by obeying a one-word command — in effect, through his compliance, saying “please.” This limit-setting program is effective in between 70 to 90 percent of dogs within a period of two months or so. In addition to these treatments for his aggression, we also recommended desensitization to car rides because we thought his reaction to traveling in the car was a result of some acquired fear.

Six months later, Chevy’s owner returned for a follow-up appointment and announced that he had been diagnosed with hypertrophic osteodystrophy — a bone disorder — and was now being treated with the powerful pain killer Rimadyl. The local veterinarian had also implemented treatment with Prozac, as we had suggested at the time of the appointment in case he was not responding as quickly or well as anticipated.

When Training Doesn’t Help Aggression

Chevy’s owner had also enlisted the help of a trainer, but his aggression continued pretty much unabated and now often took the form of snarling or lunging when she came home.

Fast forward two years: After a series of appointments with the local veterinarian and various behaviorists in our section, Chevy was considered by his owner to be getting even worse. Now he was growling not only over food and objects but was also space-guarding, was exhibiting petting-induced aggression, and was particularly aggressive whenever his neck was touched.

He was still being treated with Prozac at this time, and his owner had tried adding the anti-anxiety drug buspirone at our suggestion to see if that would help. At one re-check appointment, Chevy’s owner was again advised about the nothing-in-life-is-free program, and we tried switching his treatment to a different serotonin-enhancing drug, Zoloft.

Four years after his initial appointment, Chevy was finally considered by his owner to be doing very much better. She graded him 1.5 on a scale of 1 to 10 for his aggressiveness (where 10 was the worst she had ever seen). Chevy’s lunging at her was now occurring only about once a month, his aggression over his food was considerably less, and she could even take a stolen object from him.

Barking for Hours

That said, she was now noting that Chevy was barking for about three hours a day and seemed to be very moody at times. The new plan at this time was to try a combination of Zoloft and buspirone as “background treatment” and to use a mood-stabilizer, clonidine, on an as-needed basis to treat his occasional outbursts of hyperactivity and barking.

In follow-up phone calls, Chevy’s owner again confirmed that he was much better overall, but just when she thought she had the problem pretty much licked, there was a sudden exacerbation of his aggression to the point of viciousness in July 2011. So bad was this sudden turn of events that his owner was seriously considering euthanasia. It was almost the end of the line for Chevy — and who could have faulted his owner, who had put up with so much and tried so hard to help him overcome his demons?

The fact that Chevy had finally done so well after years of treatment and then had suddenly deteriorated into this violent form of aggression made me think that perhaps he was exhibiting the syndrome known as “rage,” a form of behavioral seizure occurring in the part of the brain with executive function over aggression. As a last-ditch effort (I have to admit) and without offering Chevy’s owner much hope, I suggested treating him with the anticonvulsant phenobarbital to see if that might help. If it did help, the diagnosis of partial seizures would be confirmed by his positive response to this therapy.

Chevy’s owner wrote to me a few weeks later and reported that shortly after starting the phenobarbital, he had ceased showing aggression toward any human, including her. Though he continued to harass the cat, she was able to separate them by grabbing him by the collar without getting bitten. This was, to her, a major breakthrough. She emailed me as follows:

“I cannot tell a lie. I was scared to death. I pulled Chevy away and allowed the cat to flee. He did not turn that aggression towards me and calmed right down.”

She went on to say that living with Chevy now was like having a different pet and went on to express her gratitude toward me and other members of the behavior section for all we had done to make his new life possible. Although not a typical presentation for “rage,” it did seem that Chevy had elements of partial seizure activity underlying his excessive and irrational aggression.

His response to phenobarbital, which was rapid and dramatic, supports this diagnosis. Perhaps his seizure-based aggression was superimposed on a generally cantankerous nature, accounting for some of his earlier, milder aggressive incidents, but seizures certainly seemed to be involved laterally. We suspect that Chevy will need to remain on anticonvulsant medication forever and, hopefully, because of this treatment, his new improved mood will continue.

Aggressive Dogs Aren’t “Bad” Dogs

Partial seizures are not common but do sometimes occur and may take many forms, including aggression, extreme irrational fear, and sometimes abnormal eating behavior. They have also been associated with tail-chasing, which you’ll remember Chevy was showing much earlier on when he was a puppy. I think that the fact that partial seizures are so rare is the reason that we initially missed this diagnosis and tried the usual measures, but the exacerbation later on finally gave away the underlying nature of his condition. The good news for Chevy’s owner is that she no longer has to contend with his aggression. The good news for Chevy is that he likely feels a lot better, therefore acts a lot better and, though he doesn’t know it, his life was saved.


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