By W. Jean Dodds, DVM
As published in Dog World Vol. 77 No. 10, October 1992
Abnormal behavior in dogs can have a variety of medical causes; it also can reflect underlying problems of a psychological nature. Your veterinarian follows a systematic diagnostic approach in searching for medical causes when a per exhibits unusual or unacceptable behavior. As summarized by Landsberg (Canadian Veterinary Journal, 31:225-227, 1990), this includes:
1) a complete patient history;
2) clinical examination and a neurological work-up;
3) routine laboratory testing of complete blood count, blood biochemistry and thyroid profiles, urinalysis, fecal exam and X-ray;
4) additional specific laboratory tests as indicated (e.g., other hormonal tests, bile acids, blood ammonia, glucose tolerance, immunological assays and tests for toxins, fungi and other infections;
5) examination of cerebral spinal fluid; and
6) more specialized neurological examinations such as an electroencephalography and computerized axial tomography scan.Diagnostic steps 1 through 3 are usually completed first; additional tests such as steps 4 through 6 are performed if indicated. If these test results prove to be negative, a veterinary behavior consultant or qualified pet behavior therapist should evaluate the dog.
Inheritance has been shown to play an important part in the behavior of both animals and humans; Plomin recently reviewed its role (Science, 248:183-188, 1990). The genetic influence on behavioral disorders rarely accounts for more than half of the phenotypic expression of behavioral differences. Each of the multiple genes involved has a small effect on behavior. Newer techniques in molecular biology should permit the identification of the genetic DNA marker sequences responsible for behavioral variation.
However, behavior is the most complex phenotype because it not only reflects the functioning of the whole organism, but it is dynamic and changes in response to environmental influences. With respect to animal behavior, applied behavioral genetics first was studied several thousand years ago because animals were bred and selected for their behavior as much as their conformation. The results can be attested to by the dramatic differences in behavior and physique among various dog breeds. Today these breeds have a great range of genetic and behavioral variability.
In recent years, many investigators have noted the sudden onset of behavioral changes in dogs around the time of puberty. Most of the dogs have been purebreds or crossbreds with an apparent predilection for certain breeds (e.g., Golden Retrievers, Shetland Sheepdogs, German Shepherds, Cocker Spaniels, Akitas, Doberman Pincschers and Rottweilers). Many of these dogs also had begun to show the seasonal effects of allergies to inhalants and ectoparasites such as fleas, followed by the onset of skin and coat disorders, including pyoderma, allergic dermatitis, alopecia and intense itching.
A typical history starts out with a quiet, well-mannered and sweet natured puppy. The dog is outgoing, has attended puppy training classes to prepare for obedience, working or show events, and comes from a reputable breeder whose kennel has no history of behavioral problems.
However, at the onset of puberty, which varies from seven months to a year in age, sudden major changes in personality are observed. Typical signs may include incessant whining, nervousness, schizoid behavior, fear in the presence of strangers, hyperventilation, undue sweating, occasional disorientation and failure to be attentive. These can progress to sudden unprovoked aggressiveness in unfamiliar situations with other animals and with people, especially children.
The owners may attribute the problems to the sex hormonal changes accompanying puberty or just the uncertainties of adolescent development. Often these animals are neutered, which appears to alleviate the behavioral problems, specifically the aggression, for varying lengths of time. For a significant proportion of these animals, however, neutering does not alter the symptoms and they intensify progressively to the point that the adult can be described as flaky, unable to handle any kind of stress, frantically circling, hyperventilating and not able to settle down. Animals used for field work and tracking often fail to follow the scent, whereas those in obedience training may lose the scent articles. Their powers of concentration are often very short and so dogs that were training very successfully at obedience appear to lag behind in a disinterested fashion. With all of these changes in behavior, the problem of most concern is unwarranted aggression. When large breeds are affected it poses a significant hazard to family members, friends and strangers.
In some cases affected animals do not show aggression but become very shy and fearful to the point that they are social outcasts and do not make acceptable house pets. These animals clearly are not suitable for show, obedience or working purposes. Some of these dogs will show extremely submissive behavior, roll over and urinate upon being approached.
The third group of dogs showing aberrant behavior consists of those that experience seizure or seizure-like disorders beginning in puberty and continuing to mid-life. These are dogs that appear perfectly healthy outwardly and have normal hair coats and energy, but suddenly experience seizures for no apparent reason. The seizures are often spaced several weeks to months apart, and occasionally they appear in a brief cluster. In some cases the animals become aggressive and attack those around them shortly before or after having one of these seizure episodes.