These activities show dysfunction in action and behavior. Alternatively, the terms behavior problem, behavior pathology, mental health disorder, or emotional disorders might be used. By comparison, many behavioral complaints are normal behaviors that are undesirable to owners (eg, garbage raiding, jumping up, predation, herding, guarding).
Abnormal repetitive behaviors are a heterogenous group of behaviors that include both stereotypies and compulsive/impulsive behaviors (see below). Although these two categories of behavior have similarities in clinical presentation and perhaps neurophysiology, they are not synonymous. In addition, underlying medical conditions might cause or contribute to these signs. Thus, until a definitive diagnosis is made, the term abnormal repetitive behavior is a descriptive term for any of the behaviors that are maladaptive, repetitive or fixed, and pathologically abnormal. Although categories overlap, clinical signs have been described as oral/ingestive (eg, pica, polyphagia, licking, gulping), neurologic/hallucinatory (eg, fly snapping, light chasing), locomotory (eg, spinning, pouncing), and self-directed (eg, acral lick dermatitis, psychogenic alopecia).
Aggression can be defined in a narrow sense (attack) or in a broader sense as agonistic behavior. In the latter case, aggression can be appropriate or inappropriate, in context or out of context, inter- or intraspecific, or a challenge or contest that results in deference or in combat and resolution.
Compulsive behaviors are abnormal and repetitive, may be variable in form, and are often fixated on a goal. They may be exaggerated, sustained, intense, and difficult to interrupt or have an element of dyscontrol in either the initiation or continuation of the behavior or the inhibition or switching between behaviors. They are generally derived from normal behaviors such as grooming, predation, ingestion, or locomotion. Compulsive disorders might initially arise in situations of frustration or conflict but become compulsive when they persist or arise outside the original context. There appears to be a genetic predisposition to the development of certain compulsive behaviors (eg, wool sucking in Oriental breeds of cats, tail chasing in German Shepherds, flank sucking in Dobermans). There is likely an alteration in serotonergic activity for most compulsive disorders in dogs and cats. However, there can be a wide range of presentations, and multiple neurotransmitters have been implicated (eg, dopamine, opiates). This may indicate an altered course of disease over time or that the diagnosis encompasses more than one disorder. Drugs that inhibit serotonin reuptake are generally most effective to enhance serotonin transmission and inhibit dopamine activity. Brain areas of interest include the prefrontal cortex and amygdalae.
Conflict arises when a pet has competing motivations or is motivated to perform more than one opposing behavior. This might occur when a dog is motivated to greet but is fearful of approach, perhaps because of previous unpleasant experiences (eg, yelling, hitting, pinning). The resultant behavior might be either a displacement behavior (see below) or aggression (when fear is an overriding factor).
This type of activity is generally a normal behavior that is performed out of context, or is “displaced,” because the animal is unable—physically or behaviorally—to execute another activity or otherwise occupy itself. This is less specific than redirected behavior (see below), in which the intended behavior is directed toward another target. When displacement activity occurs, the behavior may be out of context with the situation (eg, circling, air snapping, or even urination). Displacement behaviors may arise from conflict or frustration or be a vacuum activity.
Dominance is a concept frequently misapplied. The ethological concept of dominance refers to competitive control over a resource in a limited circumstance and to the ability of a higher-ranking animal to displace a lower-ranking one from that resource. Rank is usually defined by an ability to control the resource or by access and ability to restrict matings; however, extra-pair copulation is almost always more common when assessed by DNA analysis than it was believed to be on the basis of behavioral observations.
Dominance is not interchangeable with hierarchical rank. Ranks, particularly those that are linear and in which a “dominant” animal is identified, are largely artifacts of experimental or manipulated situations. A “dominant” animal is not the one engaged in the most fighting and combat. Most high-ranking animals seldom have to contest their right of access to a resource. Instead, high-ranking animals are usually better identified by the character and frequency of deferential behaviors exhibited by others in their social group and by their ability to respond appropriately to a variety of social and environmental circumstances. Thus, confident and assertive postures and signaling of one individual in a pair might be described as dominant if the response of the second individual is deferent or subordinate. However, dominant/subordinate does not describe the relationship between the pair, unless the response is consistent across resources and interactions. While this terminology applies to communication and signaling between members of a species (eg, dog-dog), it does not “translate” to communication between species (eg, dog-human).
Fear is a feeling of apprehension associated with the presence or proximity of an object, individual, or social situation. Fear is part of normal behavior and can be an adaptive response. The determination of whether the fear or fearful response is abnormal or inappropriate must be determined by context. For example, fire is a useful tool, but avoidance of fire is an adaptive response. If a pet is fearful of stimuli that are innocuous, such as walking on certain types of surfaces or going outdoors, such fear would be irrational and, if it were constant or recurrent, probably maladaptive. Fears usually occur as graded responses, with the intensity of the response proportional to the proximity of the stimulus. A sudden, all-or-nothing, profound, abnormal response that results in extremely fearful behaviors is usually called a phobia.
This state arises when an animal is motivated to engage in a sequence of behaviors that it is unable to complete because of physical or psychological obstacles in the environment. When pets are frustrated—such as a cat that cannot gain access to an outdoor cat that it sees through the window, or a dog that cannot get to a stimulus on the other side of a door or fence—the resultant behavior can be a redirected behavior (eg, attack of another family pet or owner), a displacement behavior (eg, stereotypic pacing), or signs associated with anxiety (eg, whining or howling). Another example of goal frustration is the dog or cat that chases a laser light toy but is unable to finish the sequence or achieve any goal. This frustration may lead to obsessive chasing of other lights and shadows.
Most fearful reactions are learned and might be unlearned with gradual exposure, although a lack of sufficient previous exposure, consequences of previous exposure, and genetic factors all play a role in how quickly or completely the unlearning might be achieved. Phobias involve sudden, all-or-nothing, profound, abnormal responses that result in extremely fearful behaviors (catatonia, panic). Phobias may develop over time—some animals develop increasingly more intense fears with repeated exposure (eg, storm phobias). However, once established, they are associated with immediate and intense anxiety when the stimulus is presented. Once a phobic event has been experienced, any event associated with it or the memory of it is often sufficient to generate the response (eg, wind, rain, or darkening sky and storm phobias). Although fears may diminish with repeated exposure and no untoward consequences, phobias can remain at or exceed their former high level for years even without reexposure. The genesis for such events in dogs is usually either extremely frightening or traumatic, or the dog itself has profound internal problems with fear (eg, genetic predisposition) so that responses to unfamiliar stimuli are excessive. Owner responses might inadvertently aggravate the problem, either by further encouraging the behavior or by adding to the fearful emotional state if the outcome for the pet is unpleasant (eg, owner anger or punishment). Phobic situations are either avoided at all costs or, if unavoidable, are endured with intense anxiety or distress.
Redirected behavior activities are directed away from the principal target and toward another, less appropriate target. When the animal is in a state of emotional arousal and is unable to reach the appropriate target, the behavior can be redirected to an alternative target if the animal is interrupted.
A stereotypy is a perseverant repetition of behaviors that are unvaried in sequence and have no obvious purpose or function. They usually derive from contextually normal maintenance behaviors (eg, grooming, eating, walking). The behaviors have been reported commonly in farm, zoo, and laboratory animal species and arise in situations of conflict or frustration related to confinement or husbandry practices. They may arise when the environment is barren or stress evoking, when the animal lacks the opportunity to display a full range of species-typical behaviors, with maternal deprivation, and as a result of neurologic disorders. It is thought that some stereotypic behaviors, at least in their early stages, may provide a mechanism for the pet to cope. For example, non-nutritive suckling in calves may assist digestive processes. Stereotypys might be associated with basal ganglia dysfunction and can be induced by dopaminergic stimulation of the striatum.