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Diagnosis of Behavioral Problems


Gary M. Landsberg

, BSc, DVM, MRCVS, DACVB, DECAWBM, North Toronto Veterinary Behaviour Specialty Clinic

Last full review/revision May 2014 | Content last modified May 2014
Topic Resources

Veterinarians must have an understanding of the behavior and development of the species, the principles of learning, and the signs of fear and anxiety to differentiate normal behavior from abnormal behavior. When presented with an animal with undesirable behavior, the first step is to exclude any medical problems that might be causing or contributing to the behavioral signs. In addition, while it is common to consider the effects of disease on behavior, stress can cause alterations in behavioral, physiologic, and immune responses, which can have variable effects on health and behavior with increasing chronicity. Stress leads to alterations in the hypothalamic-pituitary axis and in levels of dopamine, serotonin, norepinephrine, and prolactin. In animals, stress can cause or contribute to feline interstitial cystitis; dermatologic, respiratory, and GI disorders; and behavior problems such as compulsive disorders, exaggerated fear responses, and psychogenic polydipsia and polyphagia.

Diagnosis of any behavioral problem requires the identification of all behavioral and medical signs, history taking, a physical and neurologic examination, and any diagnostic tests indicated to exclude underlying medical conditions that might cause or contribute to the signs (see Table: Medical Causes of Behavioral Signs).


Medical Causes of Behavioral Signs

Medical Condition

Behavioral Signs

Illness or disease

Altered personality, lethargy, depression, withdrawal, anorexia, reduction in grooming, altered social relationships, altered response to stimuli


Central (affecting forebrain, limbic/temporal, and hypothalamic), rapid-eye movement sleep disorders

Altered awareness and response to stimuli, loss of learned behaviors, housesoiling, disorientation, confusion, altered activity levels, temporal disorientation, vocalization, change in temperament (fear, anxiety, aggression), altered appetite, altered sleep cycles, interrupted sleep (aggression/waking/activity)

Peripheral (neuropathy)

Self-mutilation, irritability, aggression, circling, hyperesthesia

Focal seizures/temporal lobe seizures

Repetitive behaviors, self-trauma, chomping, staring, altered temperament (eg, intermittent states of fear or aggression), tremors, shaking, interrupted sleep

Sensory dysfunction

Altered response to stimuli, confusion, disorientation, altered sleep cycles, irritability, aggression, vocalization, housesoiling

Metabolic / Endocrine

Feline hyperthyroidism

Irritability, aggression, urine marking, increased activity, night waking

Canine hypothyroidism

Lethargy, decreased response to stimuli, irritability, aggression


Panting, night waking, housesoiling, irritability, polyphagia, anxiety


Housesoiling, night waking

Functional ovarian and testicular tumors

Androgen-induced behaviors: males—aggression, roaming, marking, sexual attraction, mounting; females—nesting or possessive aggression of objects

Hepatic or renal encephalopathy

Signs associated with affected organ, anxiety, irritability, aggression, altered sleep, housesoiling, mental dullness, decreased activity, restlessness, increased sleep, confusion

Anemia or electrolyte imbalances



Altered response to stimuli, decreased activity, restlessness/inability to settle, vocalization, housesoiling, aggression, irritability, self-trauma, waking at night


Licking, polyphagia, pica, coprophagia, housesoiling (fecal), wind sucking, tongue rolling, unsettled sleep, restlessness


Housesoiling (urine), polydipsia, waking at night


Psychogenic alopecia (cats), acral lick dermatitis (dogs), nail biting, hyperesthesia, other self-trauma

If there is no underlying medical cause for the behavioral signs, then a comprehensive behavioral history is required to determine the diagnosis, prognosis, and treatment options. The history should include: 1) sex, breed, and age of animal (breed predispositions); 2) age at onset of condition or complaint; 3) duration of condition or complaint; 4) description of undesirable behavior; 5) frequency (hourly, daily, weekly, monthly); 6) duration of bouts; 7) any changes in pattern, frequency, intensity, and duration of bouts; 8) corrective measures tried and the response, if any; 9) any activities that stop the behavior (eg, animal collapses); 10) 24-hr schedule of animal and owner, as well as any day-to-day variability; 11) environment and housing; 12) animal’s familial history; and 13) anything else the owner thinks is relevant. In farm animals, questions should be framed within the context of the problem so that housing, management, group or herd behavior, production, and perhaps reproduction are addressed.

For each behavior problem, the "ABC" should be considered, ie, the antecedent, or what precedes the behavior; the behavior, or the description of the problem; and the consequences, or what happens immediately after the behavior. With maturity and learning, the animal’s response to a stimulus may be modified; thus, the initial events may be just as important to evaluate as the more recent events.

History might be collected in part by having the owner complete a history questionnaire before the visit, especially with respect to data about the home and housing, family, daily schedule, training, husbandry, and background. However, further interactive questioning and discussion with those responsible for the animal’s care, housing, and training are required to further evaluate the progress and development of the problem from the initial event to the present time. Having the owners bring video clips of the behaviors can further help provide insight as to the diagnosis, prognosis, and how the problem might be managed or improved.

Additional information about the pet’s personality, relationship with the owner, response to stimuli, and owner's response might be gained during the visit by observation of the pet and how it interacts with the owners. Although provoking the pet is generally contraindicated because any further repetition of the problem is ill advised for the pet and might lead to further learning, a controlled interactive assessment might include how the animal responds to other animals and people, sounds, a child-like doll, or handling, including physical examination, petting, or the application of products such as a head halter, muzzle, or body harness. The pet’s response to commands can be assessed during the visit, as well as the types of treats or toys most likely to positively affect the pet.

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