By now almost everyone has heard of the syndrome of medical hyperactivity that is supposed to affect so many schoolchildren. These children have difficulty concentrating, are not good at following directions, fidget constantly, find it hard to sit still, and are easily bored. Another name for this nebulous constellation of signs is attention deficient hyperactivity disorder, or ADHD for short. In girls, the hyperactivity component is often lacking, giving rise to a purer attention deficit disorder, just plain ADD, whereas in boys, the hyperactivity component is more common and the syndrome is often associated with aggression. Although it used to be thought that ADHD was confined to childhood years, it has come to light recently that the disorder persists throughout life, though it often goes unrecognized and undiagnosed. Typical signs of ADHD in adults include difficulty in getting started on projects, forgetfulness, procrastination, and a constant need for stimulation that manifests as thrill-seeking behavior. The question is, could dogs possibly be affected with a similar syndrome? Some say yes, and some say no.
The term hyperactivity
has vernacular implications as well as being a possible medical diagnosis. It is common for owners and trainers to refer to a particular dog as hyperactive, meaning that it runs around a lot and won't listen. According to this rather loose definition, almost all puppies are hyperactive; observation tells us that puppyhood and hyperactivity are virtually synonymous. But do all puppies grow up to be forgetful procrastinators? I don't think so. On the other hand, if we always interpret restlessness, limited attention span, and a high activity level in dogs as normal behavior, or a variation on a theme of normalcy, we will never diagnose hyperactivity.
Behaviorists' views on the existence of hyperactivity in dogs are equivocal, with opinions ranging from one extreme to the other. The head of the behavior clinic at the Veterinary Hospital of the University of Pennsylvania, Dr. Karen Overall, says that she has yet to diagnose a case of hyperactivity in dogs. On the other hand, Dr. Walter Burghart, a veterinary practitioner in Texas with a special interest in animal behavior, believes that hyperactivity is the driving force behind many of the behavior problems that we see in domestic dogs. The case can be argued both ways, depending on your point of view. In support of Dr. Overall's position, I, too, have had precious few, if any, dogs that I have confirmed as hyperactive according to the strict medical definition of the word. In support of Dr. Burghart's view, though, I have seen many dogs that could reasonably be described as overactive or hyperactive that present with a variety of behavior problems apparently secondary to this underlying disturbance. Some might say that the proof of this pudding lies in the response to stimulants, such as Ritalin and amphetamine.
The paradoxical response of hyperactive schoolchildren to treatment with the stimulant Ritalin is almost legend. I have even heard parents and schoolteachers say, "Oh, that kid's hyperactive. He should be put on Ritalin." Now, Ritalin would make a normal child tear around like a turkey with its head cut off, but for some reason it has a calming effect on hyperactive children, enabling them to pay attention and focus on the job at hand. In fact, in their book Driven to Destruction,
psychiatrists David Hallowell and John Ratey liken the effect of Ritalin on a hyperactive child to that of putting a pair of spectacles on a child that is nearsighted. It has the effect of permitting him to focus. If supposedly medically hyperactive dogs were to respond to stimulants in a similar way, you would think that this would be powerful evidence in favor of a true medical-syndrome hyperactivity. And wouldn't you know it; some hyperactive dogs do calm down when treated with stimulants. One veterinary behaviorist colleague of mine, Dr. Andrew Luescher, now head of the behavior program at Purdue Veterinary School in Indiana, employs a diagnostic test in which putatively hyperactive dogs are administered a small dose of amphetamine by mouth and their behavioral and physiologic responses are monitored for four hours thereafter. Dogs that become restless and whose heart rate and respiratory rate increases following medication are considered "normal," whereas hyperactivity is confirmed in dogs whose activity level is reduced by this treatment and whose heart rate and respiratory rate subsequently is slowed.
Dr. Burghart uses a slightly more protracted but analogous approach to diagnosing hyperactivity in some of his patients. He advises a course of the antidepressant Elavil to be given at home and for the owners to monitor and record the dog's response to this treatment. Elavil (whose very name is a pun on the word elevate
--as in elevate mood
) has stimulant properties and it can be argued that it produces a stimulant effect analogous to that of amphetamines. Again, the diagnosis is (supposedly) confirmed if owners report calming of the dog's behavior as a result of this test. Unfortunately, Elavil also produces a calming and mood-stabilizing effect by a different mechanism, leaving these conclusions somewhat open to debate.
All this talk of hyperactivity in dogs and its similarity with hyperactivity in children was initiated by scientist Samuel Corssen and coworkers in the 1970s. Corssen produced a behavioral change he called hyperkinesis in a cruel study on laboratory dogs by stressing them with inescapable random electric shocks. It is of little surprise that some of these dogs developed an increased heart rate, heavy breathing, salivation, and metabolic changes associated with stress. What is more surprising is that some of the dogs in the experiment did not
show the same signs, or at least adapted quickly. He described the traumatized responders as antidiuretic dogs because their urine production fell. Finding that these antidiuretic dogs became calmer when treated with Ritalin or amphetamine, he drew parallels with the human condition of hyperactivity. More relevantly, Corssen also found that amphetamine had a beneficial calming effect on what he referred to as naturally occurring untrainable hyperkinetic dogs--untrainable dogs that had not yet been exposed to his Frankensteinian experiment. These dogs were so labeled because they did not cooperate with his handlers and were not easily commanded. Furthermore, they fought violently against the restraining harnesses and "tried to bite and chew everything within their reach." I'm not sure whether these dogs were truly hyperactive or just smart, but either way, they were calmed following treatment with stimulants. Actually, not all naturally hyperkinetic dogs responded to amphetamine in this way; only six of eight did. Interestingly, the two that were resistant to the treatment were both wirehaired fox terriers. (No surprise there--WHFTs seem refractory to all treatments.)
Although I don't condone Corssen's methods, I believe that his results, since they already exist, are worth reference. I too have found that some apparently hyperactive dogs become calmer when treated with stimulants and have had my most memorable treatment failures with wirehaired fox terriers. Although a delightful breed, wirehaired fox terriers, like my friends the bull terriers, can be extremely perseverant in a predatory sort of way. Both breeds really need a job to do if they (and their owners) are to stay sane.
I still haven't committed as to whether hyperactivity (or hyperkinesis) really does occur in dogs. The evidence we have for it occurring is that some excitable and overactive dogs show a positive response to stimulants. It's a pharmacological diagnosis. But is this positive response to stimulants really all that specific? I don't think so. Dr. Ratey uses the expression noise
to describe the spontaneously heightened mental activity of his patients. He says that mentally noisy patients (those whose neural pathways never seem to shut down) often show a paradoxical response to stimulant drugs without necessarily having ADHD. The calming response is thus a general one that applies to all highly active individuals. The converse is also true--that more-sluggish individuals respond with increased activity. Thus the effect of stimulants appears to be one of normalizing patients, rather than some unique effect distinguishing hyperactive patients. Could it be that stimulants merely normalize dogs' behavior, too?
Another piece of evidence that detracts from the diagnostic value of the response is that all
stimulants produce a calming effect in mentally noisy folk as well as those with ADHD. It doesn't seem to matter which drug is used--amphetamine, Ritalin, cocaine, even caffeine--the calming effect is the same for these individuals. This accounts for the fact that adults with ADHD have a tendency to become addicted to stimulant drugs like cocaine--because when under the influence of such a compound, they are able to concentrate properly, perhaps for the first time in their lives. This paradoxical response also explains why some people say they feel calm rather than jittery after drinking a gallon of black coffee. Little do they know they might have ADHD. The lack of specificity of response to stimulants seems to indicate that we're not dealing with a particular neurotransmitter imbalance in the brain with ADHD but rather a problem of a more general nature--an extreme of normal behavior, perhaps.
Whatever your thoughts on the medical condition known as hyperactivity in humans or in dogs, the fact is that some dogs' (and some humans') behavior is appropriately described by this term. Take Hyper (real name), for example, a sixteen-month-old castrated male keeshond. His frazzled owner, Wendy Smith, brought Hyper to see me one June day after a particularly harrowing week. It didn't take me long to figure out the nature of the problem as we moved from the appointment desk to the consulting room. Young Hyper was totally ballistic and, according to Wendy, this was nothing new. We lurched toward the fire door separating the waiting room from the consulting room as Hyper charged backward and forward on his leash, oscillating to and fro like a shuttlecock, racing around in circles, barking, jumping up, then freezing occasionally for a few seconds, teeth chattering in anticipation of his next eruption. We apologized to the openmouthed clients in the waiting room, as I untangled the lead from Wendy's leg, and struggled onward to the consulting room. After a few short minutes of trying to discuss the problem amid the racket, we decided that discretion was the better part of valor and returned Hyper to the car to continue our dialogue in his absence.
Needless to say, hyperactivity and barking were high on the list of Wendy's complaints. As I reviewed the behavior questionnaire I noticed that the frequency occurrence of the behavior problem was reported as "all of the time." Now I knew why she looked so frazzled. Ancillary complaints were dominance-related aggression and extreme intrusiveness. In addition, Wendy reported that Hyper was overbearing when it came to affection. Although she qualified it by saying that he could be a wonderful and extremely affectionate dog, she also said that the extent of his affection was so great and he would lick her so much that she would almost literally have to come up for air. Moreover, Hyper would not obey any commands when in this demanding mode, which would occur whenever she dropped her guard. Wendy also reported that Hyper had trouble paying attention when given commands and that, try as she might, she could not get him to sit because he was always too wound up. He barked at shadows, planes, birds, insects, and people walking by, and would become excited by anything that was new in his environment.
Initially I treated Hyper using a dominance-control program to help Wendy get better control of him and to reduce his aggression to her. His exercise was stepped up and his food was switched from a performance ration to a low-protein, preservative-free diet. Although his aggression was controlled to some extent by these measures, his hyperactivity was not. At the suggestion of a colleague of mine, I had Wendy try a citronella antibark collar to control his barking. Initially the antibark collar was a big success, but unfortunately it was triggered by other dogs barking and he kept getting citronella sprayed in his face for no reason at all. This, coupled with the fact that the citronella made him throw up, led to a messy conclusion to this phase of his retraining.
It was at this time that I thought a trial with Ritalin would be in order. Wendy ran the trial at home one weekend. Hyper was given one Ritalin tablet on a Saturday night, but instead of calming him down, the medication made him tear around barking and he became even more hyperactive (how was this possible?). Wendy elected not to experiment with a second dose of Ritalin on Sunday, and with that the diagnosis of hyperactivity and the possibility of treatment with Ritalin or amphetamine went by the board. All was not lost, though, as Hyper did respond to treatment with Elavil, which seemed to bring him back to earth to some extent. It's hard to know whether this result was a paradoxical one or attributable to the more traditional calming effect of the antidepressant, because, as I mentioned, Elavil's effects can be interpreted either way. I may never know what was troubling Hyper. I wish I did because there are a lot of dogs like him, some of which show a response to stimulants and some of which do not. Without question, more studies need to be conducted to further investigate this perplexing syndrome. One thing is for sure: If a dog tears around in circles, won't listen, won't respond to commands, is impulsive, intrusive, and won't wait, it isn't necessarily hyperactive in the true medical sense of the word. To go out on a limb, I would say that such dogs do not have a psychiatric disorder homologous with ADHD in children, even though there are some intriguing parallels.
To further muddy the waters, there are a number of other problems that can lead to similar extreme behavior. I have already mentioned the possible confusion with normal puppy behavior, but there is also the all-too-common problem of mismanagement. Some dogs have no expectations made of them, have little exercise, and spend many hours alone or confined. Such dogs are bound to let rip when they finally are given some freedom. Confused owners stand there and yell at the dog, "No," "Sit," "Leave it," and all the other things they have learned at training classes, hoping that their untrained dog will suddenly see the light. Fat chance. Well-behaved dogs, like well-behaved children, require good schooling, attention when attention is due, and constant reinforcement of good behaviors. They also require a healthy lifestyle including plenty of exercise, entertainment, companionship, and clear lines of communication with the owner. All can be achieved if the owner invests time in training the dog, particularly in puppyhood. Consistent training is an essential part of the behavioral shaping process but such training should, in my opinion, be a positive experience for both the owner and the dog and it should be nonconfrontational in nature (see "O--Obedience Training").
Though not universally accepted, dietary measures may also be an important part of the management of some hyperactive dogs. It is generally believed by dog trainers and some behaviorists that certain foods exacerbate hyperactivity in dogs, as they may do in hyperactive children. The dietary culprits have yet to be identified with any precision, but high levels of dietary protein, sources of protein to which the dog is allergic, and artificial preservatives (particularly ethoxyquin) are widely touted as being involved.
One other cause of hyperactivity is metabolic dysfunction. Both hypo- and hyperthyroidism can lead to hyperactivity. Hyperthyroidism is extremely rare in dogs but can result from thyroid tumors. Hypothyroidism, on the other hand, is extremely common, and recent evidence suggests that borderline-to-low thyroid function may cause a paradoxical syndrome of increased anxiety, fearfulness, and hyperactivity. The fact that thyroid hormone receptors are affected in some cases of medical hyperactivity (ADHD) provides a fascinating link between these conditions that is worthy of further investigation. Details of the paradoxical hypothyroid syndrome are dealt with in a later section ("V--Veterinary Causes of Behavior Problems").
Before we leave the subject of hyperactivity, a word or two about the "extremes of normal" theory is warranted. You may be saying, "How can an extremely hyperactive dog be described as normal?" By way of explanation, the first question to ask is, "What is normal?" Normal is (according to the Chambers etiological dictionary) "ordinary, well-adjusted, and functioning regularly." Statistically, the normal distribution of a biological population of, say, behavior types is described by a bell-shaped curve. Most of the behavioral types fall in and around the bulge in the center of this curve, but others will lie out toward the tapering ends of the bell curve as it approaches the baseline. A small percentage of any population will lie in the nether regions of this curve, a considerable distance from the mean (average) finding. In terms of activity level this means that you would expect certain members of a population of dogs to be considerably slower and more sedentary than their "normal" peers. You also would expect a similar number of dogs to be much more active and restless than their peers. The argument about where normal finishes and where abnormal starts is a common one in behavioral circles. With some conditions (perhaps including hyperactivity), it is possible to identify individuals that conclusively fit the criteria describing an abnormal state of affairs. Dogs could be defined as hyperactive if they are more than two standard deviations from the "norm" of activity level. Note that this definition does not necessitate believing in a medical syndrome of hyperactivity, just a variation on a theme. This explanation could even encompass the Ritalin responders if you buy the "noisy" mind theory and the more general effect of stimulant drugs.
The final word about canine hyperactivity has yet to be spoken. Until that time, the behavioral camps remain divided. We are not alone in our indecision. The same debate goes on about ADHD. There are those who believe that medical hyperactivity is a contrivance, an "emperor's new clothes" phenomenon, and others who would swear by it. It has been argued that ADHDers were most likely to seek the challenge of the dangerous transatlantic crossing in the old days, and once in North America were more likely to head west in search of new frontiers. Theoretically, then, the greatest percentage of schoolchildren receiving Ritalin should be found on the West Coast. But even if this was substantiated, naysayers would argue cultural factors rather than come to a medical conclusion. You just can't win, in people or in dogs. Perhaps one day there will be some resolution to this dilemma. When that day arrives we will know for sure whether those individuals presently described as hyperactive actually do have something organically different from the rest of us or whether they're just behaving badly and looking for an excuse.
Excerpted from Dogs Behaving Badly by Dr. Nicholas Dodman. Copyright © 2000 by Dr. Nicholas Dodman. Excerpted by permission of Bantam, a division of Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.