THE MERCK VETERINARY MANUAL
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Behavioral Problems of Dogs

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When behavior of dogs is undesirable, there are three levels of consideration: 1) Behaviors within the normal range for the species, age, and breed. In these cases, the owners need guidance on how to effectively manage the behaviors. 2) Behaviors more difficult or challenging, because they might fall within or just beyond the range of what is considered normal but are particularly intense or difficult to manage. Examples include mouthing, urine marking, mounting, barking, chasing, predation, or overactivity. Also in this category might be what could be normal for the breed but unsuitable for the family and home (ie, mismatch). These cases require behavior assessment and counseling to ensure the owners have a realistic understanding of what might be achieved and to implement treatment strategies, including environmental management and behavior modification, to achieve an acceptable level of improvement for both the owners and the pet. 3) Behaviors that are abnormal or pathologic, as a result of emotional disorders or mental health issues. These may have developed as a result of genetic factors, stressful perinatal environment (prenatal, neonatal), insufficient early socialization, medical conditions affecting brain health and development, or particularly traumatic environmental events. For these pets, the prognosis may be guarded, and owner expectations altered to achieve an acceptable outcome. Treatment generally requires both environmental management and behavioral modification, often in combination with medication (natural products, diet, drugs) to improve underlying pathology and facilitate learning.

The process to diagnose behavior problems and their treatment with behavior modification and drugs has been previously described (see Treatment of Behavioral Problems). If the problem is determined to be a normal but undesirable behavior, the owners will need counseling on how to effectively provide for the pet's needs and how to reinforce what is desirable while preventing what is undesirable. For most canine behavior management problems, counseling from veterinary staff or trainers and quality resources are required, as well as hands-on guidance from a trainer. Trainers should be selected based on their credentials and screened to ensure they use reinforcement-based training techniques. Positive punishment-based techniques should not be used in training, because at best they serve only to suppress undesirable behavior and can lead to fear, avoidance, and even aggression. Management issues include inappropriate play (eg, nipping or mouthing of people); unruly behavior (eg, pulling, lunging, jumping up, mounting, overactivity); and some forms of barking, destructive behaviors, and housesoiling.

If the problem is determined to be an emotional disorder or abnormal behavior, resolution will require a combination of behavior modification techniques, modifications to the environment to prevent further problems, and medications to help reestablish a more normal mental state and facilitate new learning (see Treatment of Behavioral Problems).

Fears and Phobias

Fear is a normal response to an actual or perceived threatening stimulus or situation. Anxiety is a response to fear and agitation, or apprehension when the animal anticipates a threat or fearful situation. Phobia is an exaggerated fear response (see Phobia). The fear response may include panting and salivation, tucked tail, lowered ears, gazing away, low body posture, piloerection, vocalization, or displacement behaviors such as yawning or lip licking. While avoidance and escape is one strategy, some dogs use aggression to remove the fear-evoking stimulus and are reinforced by success (negative reinforcement).

Some of the more common presentations include the following: 1) fear of other dogs, especially those that are unfamiliar, appear threatening to the dog, or with which the dog has had an unpleasant experience; 2) fear of unfamiliar people, especially those who are novel or look, act, or smell different than those the dog is accustomed to (eg, young children); 3) fear of inanimate stimuli such as loud or unfamiliar noises (eg, construction work, trucks, gunshot), visual stimuli (eg, umbrellas, hats, uniforms), environments (eg, backyard, park, boarding kennel), surfaces (eg, grass, tile or wood floors, steps), or a combination of stimuli (eg, vacuum cleaners, car rides); and 4) fear of specific situations such as veterinary clinics or grooming parlors. Some dogs have a more generalized anxiety, in which the fearful reaction is displayed in a wide range of situations to which a “normal” pet would be unlikely to react. Although there can be a genetic component to fear and anxiety, prenatal and neonatal stressors, including maternal separation, lack of socialization (ie, unfamiliarity), or a previous unpleasant outcome during encounters with the stimulus (or similar stimuli), can also be causative factors.

Phobic responses in dogs are generally associated with loud noises (eg, thunder, fireworks, gunshots) and the stimuli associated with these events, including rain, lightning, and perhaps even static or pressure changes associated with a thunderstorm. Some fears (eg, veterinary clinics, going outdoors, entering certain rooms, or walking on certain types of flooring) may become so intense that they meet the definition of a phobia.

It is estimated that ~14% of dogs have separation anxiety, which is an inability of the pet to find comfort when separated from family members. The problem may be primary (eg, hyperattachment, dysfunctional attachment) as the puppy ages and matures; in fact, the chances of the problem developing can be reduced by having puppies regularly spend time during the day on their own (preferably in a safe haven). In other cases, the anxiety about being left alone is secondary to an event such as a change in the household or dog's daily routine, or associated with an underlying state of anxiety along with other behavioral issues such as noise phobias and separation anxiety. Anxiety may lead to destructive behavior (particularly at exits or toward owner possessions), distress vocalization, housesoiling, salivation, pacing, restlessness, inability to settle, anorexia, and repetitive or compulsive behaviors. The behaviors are exhibited when the dog is left alone and generally arise within the first 15–30 min after departure. A video recording can be an invaluable diagnostic aid to visualize the behavior and determine whether there are other concurrent signs of anxiety (autonomic stimulation, increased motor activity, and increased vigilance and scanning). The diagnosis requires that other common causes of the signs be excluded (eg, incomplete housetraining, exploratory play and scavenging, external stimuli leading to arousal and anxiety, noise aversion, or confinement anxiety). Many pets with separation anxiety begin to exhibit signs as the owner prepares to depart (eg, putting on shoes, getting keys, going to the door). When the owner is home, the dog may crave constant contact or proximity to the owner. When the owner returns, the welcoming responses are commonly exaggerated and the dog is hard to calm down.

ABNORMAL REPETITIVE BEHAVIORS

Abnormal repetitive behaviors may actually comprise a number of conditions with different pathogeneses, including compulsive disorders, stereotypies, neurologic disorders, and other forms of behavioral pathology. Therefore, until a diagnosis is made, the term abnormal repetitive behavior may better describe the clinical presentation.

Compulsive disorders may be repetitive, stereotypic, locomotory, grooming, ingestive, or hallucinogenic behaviors that occur out of context to the time and situation in which they take place, and occur in a frequency or duration that is excessive. There may be lack of control over onset or termination. Although it can be debated whether animals can obsess, they do perceive and experience concern; therefore, the term obsessive-compulsive has also been used to describe this disorder. The diagnosis should start with a description and observation of the behavior, including video recordings if necessary. Because there is likely a genetic component for many compulsive disorders, the signalment and age of onset is also important. For example, German Shepherds and Bull Terriers are known to spin or tail chase, while a genetic locus for flank sucking has been identified in Doberman Pinschers. The problem may first arise as a displacement behavior when the dog is frustrated, conflicted, or highly aroused. Lack of predictability in the daily routine, alterations in the environment, unpredictable consequences, lack of sufficient outlets for normal behaviors, and chronic or recurrent anxiety might be initiating factors. At this point, if the owners can teach appropriate acceptable alternative responses (eg, sitting before greeting or play as an alternative to spinning) and provide constructive alternatives (eg, feeding from toys), the problem might be resolved. However, as the frequency or intensity increases, the behavior may become compulsive. The diagnosis is considered to be a compulsive disorder when the behavior interferes with normal function or when it becomes independent of (or emancipated from) the inciting stimulus. There is likely altered serotonin transmission.

Stereotypies are defined as repetitive behaviors that are unvaried in sequence and have no obvious purpose or function. They may arise when the environment lacks sufficient outlets for the dog to engage in normal behaviors, or when caused by maternal deprivation or as a result of a neurologic disorder. It is possible that stereotypic behaviors, at least in their early stages, may provide a coping mechanism for the pet. Stereotypies might be induced by dopaminergic stimulation.

Although most dogs respond to drugs that inhibit serotonin reuptake including the SSRIs and clomipramine, alterations in other neurotransmitters may play a role, eg, dopamine, endorphins, N-methyl-D-aspartic acid (NMDA). Because medical problems might be the cause of the signs, these should first be excluded. In cases in which the physical examination, history, and diagnostic testing do not clearly identify the cause, a therapeutic response trial might be indicated (eg, anticonvulsants to exclude focal seizures as a cause of fly snapping or light chasing; clomipramine or fluoxetine to exclude compulsive disorders). (Also see Table 1: Clinical Presentation and Medical Differentials for Compulsive DisordersTables.)

Table 1

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Aggression

Aggression is the most common problem in referral practices across North America, approximating 70% of the caseload. It is also a major human concern, because at least 5 million people are referred to the hospital each year in the USA alone for treatment of dog bites. Most forms of aggression, except for predation, are distance-increasing behavior (ie, the dog is attempting to actively increase the distance between itself and the stimulus). There are many types of aggressive behaviors with different motivations; however, fear, anxiety, conflict (uncertainty), genetics, and learned responses generally play a role in most cases; however, in some cases the behavior may be abnormal or pathologic. The effects of early development (prenatal, postnatal), socialization, and previous experience all play a role in development of aggression.

Aggression refers to threatening behavior or harmful attacks and can range from subtle changes in body posture, facial expressions, and vocalization to biting. Dogs that are easily aroused are at high risk of aggression, because their decision-making is affected by their physiologic state (ie, flight or fight). For treatment to be effective, the pet's anxiety and arousal must first be managed by avoiding situations or staying below the threshold at which aggression might arise. Some or all of a combination of reward-based training, behavior products that can help to better manage the pet, and medications to help achieve a behavioral state most conducive to new learning is required to successfully modify the behavior to achieve desirable outcomes and countercondition the pet to the stimuli that incite aggression.

Before treating aggression, the practitioner must assess the potential risk of injury. All stimuli that might incite aggression should be accurately identified to ensure initial safety. Predictability is a critical issue in prognosis, both to prevent further incidents and to develop a stimulus gradient for treatment. The signalment, environment, history, and target of the aggression also provide invaluable information as to whether the problem might be safely and effectively managed. The type of aggression is an additional factor—some can be managed and improved, whereas others require prevention. Finally, the clinician must assess the ability of the owner to effectively and safely prevent the problem. Aggression that is unpredictable, arises during relatively benign interactions, involves targets that cannot realistically avoid exposure to the aggressive dog (eg, young children, other household pets), or is performed by a large dog or in an uninhibited manner worsens the prognosis. Any medical condition that might cause or contribute to aggression must be identified, because they are important factors in diagnosis, prognosis, and treatment. (See www.esvce.org for risk assessment guidelines.)

Fear is the underlying cause of most forms of canine aggression. It is triggered by a stimulus that is threatening to the dog. When the aggression is a direct response to a challenge or confrontation, it might be referred to as defensive aggression. Fearful dogs may try to avoid the stimulus but become aggressive if they cannot escape (eg, leashed, confined, cornered, or physically grasped), are motivated to maintain their place (eg, on property, between the owner and stimulus, near food or toy), or if they learn that aggression is successful at removing the threat. Inadequate socialization, learning, genetics (temperament), reinforcement of aggressive behavior (eg, retreat of the stimulus), and associating a negative outcome with the stimulus (eg, punishment) can all lead to the development of fear-related aggression. The diagnosis is based on identifying signs of fear as well as the history beginning with the first event, because dogs can exhibit fear at the initial exposure but with time may display a more offensive form of aggression (without threats) when they learn it can be successful. (For treatment of fear-related and other types of aggression, see Treatment of Fears, Phobias, Anxiety, and Aggression.)

Possessive aggression is most likely to arise when a person or an animal approaches the dog while it is in possession of something it wants to retain. Pets in the process of ingesting or chewing an object might be more likely to display aggression, but the behavior can also be seen in dogs near an object. Aggression is most commonly displayed when in possession of highly motivating food, treats, chew toys, stolen items, or even sleeping places. While genetics and early experience play a role in development, the relative value of the object to the pet and the threat of losing the object to another dog or person determine whether the pet is likely to be possessive. Items that are novel or scarce may be more desirable. Fear and defensive behavior also play a role if the owners threaten, punish, or confront the pet when it takes an object or has it in its mouth. The dog may also learn that it can successfully retain the object with aggression.

The problem might be prevented by tossing the puppy high-value treats whenever the owner approaches or passes by the food bowl, and by offering a high-value treat or toy whenever the puppy voluntarily gives up another toy or chew. Food bowls, toys, and chews should not be removed by confrontation, because this can contribute to an increase in anxiety and aggression when approached. In adult dogs, the problem should be managed by preventing access to these items or confining the dog when it is given items over which it might be possessive and by training the dog to give and drop on cue (beginning with items of low value for high-value rewards). If safety is an issue (ie, the dog may hurt itself by chewing on the item), it may be possible to trade the object for one of higher value. Providing more toys and multiple small meals (eg, in feeding toys) may reduce the value and novelty of the resource.

Aggressive play is a normal puppy behavior, which may persist into adulthood as a result of genetics, neotinization, and learning. When puppies play aggressively with other puppies, they may nip and bite but will generally resolve the conflicts among themselves. However, if the problem becomes excessive, owner intervention may be required to redirect the dog's activities into other forms of play (eg, feeding toys) or to interrupt the behavior with commands or a leash and head halter. If play with people escalates to biting, the interaction can be immediately stopped (negative punishment) and resumed when oral play ceases (positive reinforcement). Alternatively, a leash and head halter or verbal distraction ("off") can be used to interrupt play biting. In all interactions, the puppy should be taught to sit before given anything of value (eg, food, toys, affection). In addition, the puppy should be engaged in regular alternative acceptable forms of play, including fetch, tug games, and manipulation and chew toys. Punishment should not be used to stop play, because it can lead to fear of the owner, defensive aggression, or conflict-induced aggression, or serve as inadvertent reinforcement for some puppies.

Aggression is directed toward a third party when the dog is prevented or unable to exhibit aggression to its primary target. This type of aggression is most commonly described when the dog bites the owner as he or she grasps or restrains the dog when trying to prevent or break up a dog fight. Similarly, dogs that might be aggressive toward a veterinarian might bite the person restraining the dog. Redirected aggression arises as a result of the frustration or interruption of other forms of aggression or arousal.

Aggression directed toward family members is often mislabeled as dominance or status-related aggression. However, aggression toward family members generally arises from fearful or defensive behaviors, resource guarding, redirected behavior, or situations of conflict (competing emotional states and unpredictable consequences). In some dogs, the problem may be traced back to the owner's attempts to inhibit excessive play aggression (see Play Aggression).

When a dog successfully uses aggression to achieve a goal (retaining a resource) or remove a threat, the pet learns that aggression is successful (negative reinforcement). If the owner continues to threaten, confront, challenge, or punish the pet, some dogs may inhibit their responses, but a large proportion become more aggressively defensive. When dogs are resting or sleeping, chewing on a favored object, or no longer desirous of human affection, they may respond with either deferent displays or threats. However, if the owner continues to approach, tries to remove the resource, or attempts to pet the dog despite its signaling, aggression may escalate and future signaling may be lost. The owner-pet relationship can quickly deteriorate as the dog becomes more wary and defensive while the owner becomes more fearful and/or confrontational.

Genetic factors and early experience likely also play a role; many of these dogs are easily aroused, excessively fearful, or may have emotional disorders or behavioral pathology (see below). Other cases are primarily a result of learning. Aggression when grabbing the collar or during bathing, nail trimming, or ear cleaning is a defensive response. Interrupting a pet that is aroused may lead to redirected aggression. Therefore, when a dog is presented for aggression toward family members, it can be difficult to determine the dog's underlying motivation because each incident has added to prior learning, fear conditioning, and underlying conflict. Dominance might refer to the relationship between two individuals of the same species within a social group, as described by actions, interactions, and intraspecific communication/signaling. These relationships are not established by aggression of the dominant individual but rather by the deferent signaling of others. Relationships between species, particularly dogs and people, are established through early socialization, the personality of the individual, and what it learns from its observations and interactions with family members. Physical techniques intended to assert dominance (eg, pinning, rolling over) and verbal discipline (yelling "no") are therefore ill advised and can result in fear, anxiety, and further aggression.

Dogs with impulse control aggression may respond with aggression to relatively benign interactions with family members. In some lines of English Cocker Spaniels and English Springer Spaniels, this aggression is associated with alterations in serotonin in blood samples or CSF.

When aggression is excessive, unpredictable, and disproportionate to the level of threat, safety is a serious concern and the prognosis generally guarded. However, when behavior is abnormal or pathologic, substantial improvement might be achieved with a combination of drugs (eg, SSRIs) and behavior modification.

Dogs in the same group or household usually avoid conflict without aggression. Communication is based on dominant and submissive signals, with the deference of one of the two individuals to avoid escalation of the encounter. Dominance is a relative concept—the dog that displays deferent signaling may vary between resources and situations. Aggression between individuals living in the same household is generally an abnormal behavior caused by fear and anxiety, redirected aggression, impulse dyscontrol, or poor intraspecific communication skills as a result of genetics or lack of early socialization and compounded by experience and learning. Redirected aggression and competition over a valued resource may also lead to aggression between dogs in the home.

Owners may play a role by inadvertently supporting or encouraging a dog during an encounter in which it would normally defer. Age or illness may also play a role, if the way in which one dog signals or responds to the other is altered. Male-to-male aggression may have underlying hormonal factors that can be improved by neutering; however, learning may play a role in maintaining aggression.

If any situations arise in which the dogs are unable to resolve conflicts without aggression or injury, behavioral guidance should be sought. Aggression toward unfamiliar dogs and those that are not members of the family group are likely fearful, possessive, protective, or territorial.

Aggression may be displayed when the dog is approached in its territory. Territory can be stationary (eg, yard, home) or mobile (eg, car). What defines the behavior as territorial is that the dog does not display fear to similar stimuli when outside its territory. Fear, anxiety, defensive, and possessive behaviors may all be components, because the pet is most likely to display the behavior toward unfamiliar stimuli, and the motivation to escape or avoid (flight) is decreased or absent when the pet is on its own property. Learning (negative reinforcement when the stimulus retreats) and fear conditioning (unpleasant outcomes such as yelling, discipline, and confinement) can also play a role.

This is one of the most dangerous types of aggression, because there is usually no warning. The attack is intended to kill prey, and the bite is uninhibited. The sequence of events may include stalking, chasing, biting, and killing. Young children and babies may be at risk because their size and behaviors mimic those of prey. Although extensive socialization to a species might reduce predation toward that species, the behavior may be enhanced when predatory individuals are together in a group. Predation is a normal and dangerous canine behavior; thus, any dog that exhibits the behavior must be prevented from opportunities to repeat it.

Any disease that causes pain or increases irritability (eg, dental disease, arthritis, trauma, allergies) can lead to aggression. The dog may become aggressive when it is handled or anticipates handling. Organ dysfunction (eg, renal, hepatic), CNS disease, and endocrinopathies (such as hyperadrenocorticism, functional testicular and ovarian tumors, and thyroid dysfunction) might also contribute to irritability and aggression. (Also see Table 2: Medical Causes of Behavioral SignsTables.) While hypothyroidism is more likely associated with lethargy, dermatologic signs, and heat seeking in the early stages, it has been suggested that dogs might display an increase in aggression, particularly toward family members. Treatment should likely be reserved for cases in which diagnostic tests are also consistent with hypothyroidism, because excessive supplementation could lead to a hyperthyroid state (with associated medical and behavioral consequences). Treating the medical problem may resolve the aggression, but the behavior, once learned, may persist.

Maternal aggression may be seen in intact females with a litter of puppies or in females with pseudocyesis. It can be directed toward people or other animals. Signs of aggression arise when the bitch's puppies or toys that mimic puppies are protected, and the aggression should resolve when the hormonal state returns to normal and/or the puppies are weaned. The term maternal aggression has also been used to describe the aggression or cannibalism directed toward the puppies by the bitch. Although the problem may have a genetic component, it is reported to occur more frequently after a first litter. Ovariohysterectomy can prevent further incidents.

Treatment of Fears, Phobias, Anxiety, and Aggression

Before implementing specific therapy to manage, improve, or resolve a behavior problem, some common elements that apply to most cases should be considered. The initial discussion should focus on 1) an understanding of normal behavior as it relates to the problem, 2) learning to read pet body language and facial expressions, 3) ensuring that all of the pet's needs are adequately being met, 4) reviewing the principles of learning and reinforcement-based training (predictable consequences), and 5) managing both the environment and the pet to prevent further incidents. The cause, diagnosis, and motivation behind the behavior should be reviewed. Finally, the owner should be given a prognosis with realistic expectations for both short- and longterm outcomes.

In most cases, treatment focuses on changing the pet's emotional response with the stimulus (counterconditioning) and/or replacing the undesirable response with one that is desirable using reinforcement-based techniques (response substitution). However, dogs that are highly aroused respond with autonomic fight-or-flight responses and tend to make reflexive responses. Therefore, arousal must be reduced before treatment can proceed. This can be achieved by training the dog to settle on cue, by minimizing the intensity of the stimulus during exposure (desensitization), or by using management devices such as head halters that can change the dog's focus and help it to settle, and with drugs or natural products that reduce anxiety and behavioral pathology. Early intervention with medication may be necessary to achieve success and can be in the best interest of the fearful, anxious, or phobic pet.

There are common elements to the treatment of fear, anxiety, phobias, and most types of aggression. The first step in the treatment program is to identify each situation stimulus or interaction in which the problem might arise, so that a preventive program can first be implemented. Prevention ensures safety (eg, in aggression cases), prevents further damage to the household or injury to the pet, avoids further anxiety-evoking situations for the pet, and ensures no further aggravation of the problem through fear conditioning (ie, unpleasant outcomes) and learning (ie, negative reinforcement if the stimulus retreats).

Prevention can be most effectively achieved by identifying and avoiding any situation in which the dog might be exposed to the stimulus. A leash and head harness, leash and body harness, or verbal commands (when effective) can also prevent access to the stimulus. If avoidance cannot be ensured and aggression is a possibility, then a basket muzzle might be the best alternative.

A common starting point to begin to reduce anxiety, improve communication and training, teach self-control, and allow the pet to control its consequences/outcomes is to establish a program of structured interactions in which the dog is not given anything it values (or wants) until it sits (or lies down). If the owners' response is consistent and predictable by ensuring the pet sits (or lies down) every time a treat (food or toy) is given, the leash is attached, the pet goes in and out of the door or car, or the pet wants affection, the dog will soon learn that the sit or down action is required to get the reward, at which point gradually longer and more relaxed responses can be taught. This is sometimes termed structured interactions, predictable consequences, learn to earn, or “saying please.”

Because the ultimate goal is to successfully expose the pet to controlled levels of the stimuli while achieving calm and positive outcomes, it is necessary to determine what behaviors need to be trained to achieve desirable outcomes during exposure training. For example, if problems arise indoors, the dog may first need to learn a focused sit, a relaxed down, and a mat command (or other location such as room or crate). A drop or give command and a come or recall may also need to be trained. When problems arise outdoors, sit and focus or down and settle may also be useful, but loose leash walking, backing up, or turning and walking away may be the best options for stimulus exposure. These behaviors should be learned reliably and consistently in a variety of environments with a minimum of distractions before the owners proceed to a graduated stimulus exposure (see Counterconditioning and Desensitization and see Response Substitution).

By identifying a range (gradient) of the pet's most favored rewards, the most desirable can be used for training and shaping new behaviors that approximate the final goal; less-motivating rewards can then be used to ensure immediacy and timing of previously learned commands. In addition, a way to minimize and control the intensity of the stimulus will also need to be designed (eg, volume, distance, location). Exposure exercises can then be implemented by setting up situations in which high-value rewards are used to reinforce the desired behavior and condition a positive response during exposure to low-intensity stimuli and gradually proceeding through more intense stimuli. Setbacks can be avoided by determining the level of stimulus intensity at which a calm and positive outcome can be achieved and reinforced, and with the use of management devices such as a head halter (sit, reorient head, turn and walk away) or front control body harness (turn away from the situation) to ensure safety and success. Drugs and natural therapeutics might be used concurrently in dogs with excessively intense or abnormal behaviors to enable the successful implementation of behavior modification.

For noise phobias, controlled exposure can best be achieved through recordings that can be gradually increased after each successful session of desensitization and counterconditioning. Concurrent behavioral management to reduce stimuli (with sound proofing, ear covers, eye covers, crate covers, or white noise) and develop a safe haven to help the pet settle might also help the pet to cope. For separation anxiety, once a regular routine of play, exercise, and training is established, any additional reinforcement should focus on shaping gradually longer inattention sessions when the pet rests or occupies itself with favored chew and food- or treat-filled toys, ideally in a comfortable safe haven (bed, crate, or room) where the owners can house the pet while gradually increasing their time away. Any attention- or affection-soliciting behavior should be ignored, unless the pet is sitting or lying down calmly (sit for all interactions) or resting on its bed or mat. Visual and auditory cues that signal departure should be avoided if possible; alternatively, they can be decoupled from departure by exposing the pet while remaining home, and associating with play and treats (counterconditioning). In addition to preventive and environmental management strategies and behavior modification, drugs or natural therapeutics can be used to reduce underlying fear, anxiety, arousal, reactivity or impulse dyscontrol to help facilitate learning; to improve underlying behavioral pathology; and in many cases to improve the behavioral well-being of the pet.

For impulsivity, generalized anxiety disorders, excessive stimulus anxiety, and phobias, selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) are commonly used. Because fluoxetine has been evaluated in and licensed for dogs, it is generally the first choice of the SSRIs, although fluvoxamine, sertraline, paroxetine, and citalopram might be alternatives when fluoxetine is insufficiently effective or adverse effects such as anorexia are an issue. SSRIs are also used to treat compulsive disorders. Among the TCAs, clomipramine is licensed for use in dogs and is an alternative to fluoxetine for the treatment of anxiety disorders and phobias. Because clomipramine is the most selective of the TCAs to inhibit serotonin reuptake, it could be used for compulsive disorders, as an alternative to SSRIs. Other TCAs might be selected for their more potent antihistaminic effects (eg, doxepin, amitriptyline), whereas imipramine has been used as an aid in improving sphincter control with behavioral incontinence. Although the full effect might not be achieved for 3–4 wk, some effect might be noted in the first week. For some compulsive disorders, especially those in which there is a self-traumatic component, gabapentin or carbamazepine might be used concurrently, whereas in those cases in which focal seizures might be causing the behavioral signs, levetiracetam, phenobarbital, or potassium bromide might be used in a therapeutic response trial.

When an anxiety-evoking event can be predicted (eg, thunderstorms, fireworks, owner departure, visit to the veterinarian, car ride, exposure to dogs or strangers on a walk, visitors coming to the home), a benzodiazepine can be given with the antidepressant ~1 hr before the event. Because benzodiazepines have variable effects and relatively short half-lives, their efficacy, dose, and duration should be determined in advance of their therapeutic use. Clonidine, trazodone, or propranolol are other options that might be used adjunctively with SSRIs ~1 hr before an expected fear-evoking event (eg, thunder, fireworks, owner departure). In some refractory anxiety cases, trazodone, clonidine, a benzodiazepine such as clonazepam, or perhaps gabapentin might be used concurrently with an SSRI.

Buspirone, a nonsedating anxiolytic, is another option for ongoing use. Caution should be exercised when using anxiolytics, because some may disinhibit fearful dogs, which could lead to increased confidence and aggression.

Selegiline, which is licensed in North America for treatment of cognitive dysfunction syndrome in dogs, is also licensed for treatment of emotional disorders or chronic anxiety in Europe.

Natural products might be used alone or adjunctively with drugs or other natural products to help calm or reduce anxiety, although evidence of efficacy is more limited. A number of studies support the use of pheromone therapy. Adaptil™ simulates the intermammary-appeasing pheromones produced by the lactating bitch and is available as a spray, diffuser, or collar. Pheromones have been used for anxiety associated with car rides, veterinary visits, separation anxiety, storm and fireworks aversions, and to reduce the stress of adoption and aid socialization. A calming or anxiety-modulating effect has been reported for alpha-casozepine (Zylkene®, a milk protein hydrolysate), Harmonease® (containing Magnolia officinalis and Phellodendron amurense), l-theanine (Anxitane®) and Sin-Susto™ (a Souroubea plant blend), and aromatherapy (with lavender). In addition, studies with l-tryptophan in combination with a low-protein diet have demonstrated a possible reduction in some forms of aggression. A commercial diet also has been developed that combines l-tryptophan and alpha-casozepine (Royal Canin Calm®) that might aid in reducing stress and anxiety.

Hyperactivity

Although hyperactivity or attention deficit disorder has been poorly documented in dogs, there have been published cases studies of dogs with excessive motor activity and an altered ability to acquire new tasks (learn), sometimes accompanied by stereotypic behaviors. It may be particularly difficult to train such dogs to behaviorally settle. There may also be signs of sympathetic activity even at rest (eg, increased heart and respiratory rate, vasodilation). Affected dogs may respond to treatment with methylphenidate. If no improvement with an initial dose of 0.25–0.5 mg/kg bid, the dosage can be gradually increased every few days to a maximum of ~2 mg/kg until a measurable therapeutic response is seen (reduced motor activity, heart rate, respiratory rate, repetitive activities), provided no adverse effects develop. Differential diagnoses include impulse control disorders that might respond to SSRI therapy, and normal behaviors in dogs with behavioral needs that are not being adequately met. In fact, it can be quite challenging to meet these needs in some breeds and individuals, depending on the home and family.

DESTRUCTIVE BEHAVIORS

Many of the destructive behaviors, including chewing, stealing, garbage raiding, and digging, are normal exploratory behaviors that arise when the pet is unsupervised and not otherwise engaged in more desirable activities. A regular daily routine with sufficient reward training, exercise, and social enrichment can help to ensure that these behaviors do not arise when the owners are home, although varying degrees of supervision may be required. When the owners cannot supervise the dog, it should be provided with adequate outlets for exploratory play in the form of chews, food-stuffed toys, or manipulation toys, or in the case of outdoor dogs, perhaps even a designated area for digging. These dogs may also need to be confined away from the areas in which problems might arise or housed in crates, pens, or runs to prevent access to potential targets of destruction. Some dogs engage in destructive behaviors because of anxiety (eg, separation anxiety, confinement, noise phobias). Together with the history, videotaping or camera monitoring is generally the best way to diagnose behavior problems that occur when the owner is absent, as well as assess response to treatment.

Eating Disorders

Behavioral problems related to ingestion include those in which food intake is excessive (polyphagia), inadequate (hyporexia), or too fast (gorging); water intake is excessive (polydipsia); and nonfood items (pica) or feces (coprophagia) are eaten. Medical causes should be excluded first. Some dogs that scavenge do so as a normal component of food acquisition and are reinforced by success. Coprophagia may occasionally have a medical cause, but normal maternal behavior includes consumption of feces and urine of young puppies. In addition, as part of exploratory behavior, many dogs are attracted to and may ingest feces, compost, and prey (dead or live). Similarly, while some dogs with pica and polyphagia have compulsive disorders, many dogs, especially puppies, begin to chew and ingest nonfood items as part of investigative and exploratory behavior.

Dogs with hyporexia may have an anxiety disorder, and some may develop specific taste preferences and aversions that reduce what they will eat.

Many feeding problems can be improved through a work-for-food program in which dogs are given food as reinforcers for training, with the balance placed inside toys that require chewing or manipulation to release the food. This encourages exploration, makes feeding an enjoyable, time-consuming, and mentally challenging activity, and can limit the quantity consumed and prevent gorging. As with most behavior problems, correcting feeding problems needs to be accompanied by management strategies to prevent access to potential targets at any time the dog cannot be supervised or actively engaged in other chew and play behaviors.

Elimination Behavior Problems

Dogs may soil in inappropriate locations because of inadequate or insufficient training, as a marking behavior, or as a result of fear or anxiety. However, pain, sensory decline, cerebrocortical disease including cognitive dysfunction, and any medical condition that leads to increased volume, more frequent elimination, pain on elimination, or lack of control, must first be excluded as potential causes or contributing factors.

A detailed behavioral history is necessary to determine whether the dog has ever been housetrained. If not, a housetraining regimen should be reviewed in which the focus is solely on reinforcement of elimination in desirable locations rather than punishment of elimination in inappropriate locations. This requires the owner to accompany the dog to its elimination area (eg, outdoors), reinforce elimination, supervise the pet indoors to prevent or interrupt any attempts at elimination (perhaps with the aid of a leash to ensure continuous supervision), and return the pet to its elimination site at appropriate intervals or if there are signs that the pet is ready to eliminate (eg, sniffing, heading to the door, sneaking away). When the owner is not able to supervise, a combination of scheduling (ensuring that the pet eliminates before departure and having someone return to take the dog to its elimination area before it must eliminate) and confinement training/prevention are required.

Pets can either be confined away from areas where they might eliminate or kept in an area where they will not eliminate, such as a pen, room, or crate, where the dog eats, plays, or sleeps. Alternatively, the dog can be provided with an indoor elimination area (eg, paper, indoor puppy potty) within its confinement area where it can relieve itself when the owner is gone. Puppies obtained from pet stores or any location where they have been extensively caged may be more difficult to housetrain, because they have never had to inhibit elimination and may have learned to play with or eat feces.

Although marking is most often seen in intact males as a form of social and olfactory communication, it is also seen in females (especially when in heat) and in neutered males and females, often as an overmarking of other odors (eg, where other pets have urinated, or on items such as blankets with the residual odor of other dogs, people, or cats). Some dogs will mark when they visit unfamiliar households, especially when another dog's odor is present. There is often a typical posture of a raised or partially raised leg when the surface to be marked is vertical. Fecal marking is uncommon.

While marking is likely a component of normal communication, it is unacceptable when it occurs indoors. Neutering intact males will reduce the behavior, and good supervision can prevent or inhibit most marking. As with housesoiling, dogs should be confined away from areas that might be marked when owners are not able to supervise. Marking that is related to anxiety may be reduced by identifying and treating the cause, perhaps with the aid of drugs or natural products that reduce anxiety.

Dogs may eliminate when they are overly excited, such as when greeting people. Some dogs will urinate when showing submissive postures (eg, crouching to the ground or turning over to expose the belly) or when highly aroused. Because loss of urine control may be associated with a concurrent desire to both greet and show deferential behavior, many cases may be due to conflicting behavioral motivations. Treatment should focus on avoiding the stimuli (reaching, approach, eye contact) that incite the behavior and avoiding any punishment during greeting, which would add to fear and conflict behaviors. Acceptable alternative behaviors that are incompatible with excitable greeting or deferent postures can be taught, such as a relaxed sit, or any game or “trick” the pet may have learned such as fetch or giving a paw. Phenylpropanolamine might increase sphincter control, whereas imipramine may improve control and reduce anxiety.

Dogs with separation anxiety or other fears and phobias (eg, thunderstorm phobia, firework phobia) may soil during these times..

Aging and Cognitive Dysfunction

The aging process is associated with progressive and irreversible changes in body systems that can affect behavior (see Medical Causes of Behavioral SignsTables and see Medical Causes of Behavioral SignsTables). In older pets, these might include hepatic or renal failure, endocrine disorders (eg, Cushing disease), pain, sensory decline, or any disease affecting the CNS (eg, tumors) or circulation (eg, anemia, hypertension). To diagnose the cause of behavioral signs in a geriatric dog, a detailed history, physical examination, neurologic evaluation, and diagnostic tests are required to exclude potential medical causes of the presenting signs. Many owners do not report these signs, perhaps because the owners think they are insignificant or assume little can be done. Yet in one study, 30% of dogs 11–12 yr old and nearly 70% of dogs 15–16 yr old had signs consistent with cognitive dysfunction syndrome (CDS). A more recent Internet survey estimated CDS in 14.2% of dogs >10 yr old, with prevalence increasing with age, but >85% of these had not been diagnosed. It is therefore essential that owners be informed of the importance of reporting signs when they arise and for veterinarians to take a proactive approach in asking owners about behavior at each visit. Early detection provides the best opportunity to improve signs and slow the decline of cognitive function.

Aging dogs may exhibit a decline in cognitive function (memory, learning, perception, awareness) that manifests as one or more of a group of clinical signs. These are sometimes referred to by the acronym DISHA and include disorientation, interactions, sleep-wake cycles, housesoiling, and activity changes (which may be decreased or increased and repetitive). In addition, anxiety, agitation, and altered responses to stimuli are frequently reported. The first and most prominent sign of brain aging is a decline in learning or memory, which is generally impractical for pet owners to assess. However, neuropsychologic testing of older dogs has documented memory decline beginning at 6–8 yr of age and learning deficits by 9 yr of age. CDS in dogs is analogous to the early stages of Alzheimer disease in people, both in clinical signs and brain pathology. As with people, some pets show minimal to no clinical impairment with age, whereas others develop varying degrees of deficits.

Treatment should first focus on environmental enrichment (both physical and mental stimulation), which has been shown to slow cognitive decline and improve the signs of CDS. Selegiline is a monoamine oxidase B inhibitor that may improve the signs of CDS by enhancing dopamine and other catecholamines in the cortex and hippocampus and by decreasing free radical load. Propentofylline, which is licensed in Europe and Australia for the treatment of dullness, lethargy, and depressed demeanor in old dogs, may increase blood flow and inhibit platelet aggregation and thrombus formation.

A number of natural products, including diets and supplements, have also been shown to have beneficial effects in improving the signs and potentially slowing cognitive decline. Two such diets are Canine b/d®, which is supplemented with fatty acids, antioxidants, and dl-alpha-lipoic acid and l-carnitine to enhance mitochondrial function, and a specialized Purina One® diet that uses botanic oils containing medium-chain triglycerides to provide ketone bodies as an alternative source of energy for aging neurons.

Other natural supplements that have demonstrated efficacy in improving cognitive function include Senilife®, which contains a combination of phosphatidylserine, Ginkgo biloba, resveratrol, and vitamins E and B6; Activait®, which contains phosphatidylserine in combination with α-lipoic acid, carnitine, fatty acids, glutathione, and other antioxidants; S-adenosyl-l-methionine (Novifit®); and apoaequorin (Neutricks®), a calcium-buffering protein found in jellyfish.

Last full review/revision May 2014 by Gary M. Landsberg, BSc, DVM, MRCVS, DACVB, DECAWBM; Sagi Denenberg, DVM, DACVB, Dip. ECAWBM (Behaviour), MACVSc (Behaviour)

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