Merck Manual

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Professional Version

Behavioral Problems of Cats


Gary M. Landsberg

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

Sagi Denenberg

, DVM, DACVB, Dip. ECAWBM (Behaviour), MACVSc (Behaviour), North Toronto Veterinary Behaviour Specialty Clinic

Reviewed/Revised May 2014 | Modified Oct 2022

As with dogs, undesirable behavior might be 1) normal behavior but undesirable for the owners (eg, climbing, scratching, and excessive nocturnal activity); 2) behaviors that fall within the range of normal but are at or near the limits, excessive in intensity or frequency, and particularly challenging or disturbing for the home environment (eg, play biting, petting-induced aggression, overexuberant play, play/predation, vocalization, asocial, litter box avoidance); or 3) behaviors that are abnormal, pathologic, or incompatible with living in the home (eg, intercat aggression, fear and avoidance, urine marking). In most cases of normal but undesirable behaviors, the owners require guidance and resource material on meeting the behavioral needs of cats and understanding learning principles to reinforce what is desirable while preventing what is undesirable. When behaviors are at or near the limits of normal, a more in-depth behavior assessment is needed to discuss realistic goals for what might be achieved, how the environment might be managed, and how the behavior might be modified. In some households, it may be impractical to make the changes necessary to achieve an endpoint that meets the owner’s needs. In cases when the behavior is abnormal or incompatible with the home environment, a behavior consultation is required to diagnose, determine the prognosis, implement behavior and environmental modifications, and dispense drugs or supplements when indicated to achieve a sufficient level of improvement for the owner and the cat. The most common behaviors seen by veterinary behaviorists are elimination (undesirable toileting and marking) and aggression. Because aggressive encounters in cats may be overt or subtle and passive, their frequency may be seriously underestimated.

For both prevention and treatment, it is important to first ensure that the behavioral needs of the cat are adequately met. This is a particularly important consideration for cats housed exclusively or primarily indoors. Although individual variability in expression can be extensive, a cat's primary behavioral needs include eating (hunting), drinking, elimination, security, play and exploration, climbing, perching, and scratching. Specifically, hunting and feeding needs might be better addressed by giving food in small portions throughout the day and placing food or treats inside toys that require some manipulation to release the food (batting, chasing, rolling, pawing). To add an element of hunting, the cat can be given opportunities to chase, pounce on, and bite toys the owner dangles or pulls in front of the cat.

Play appears to be motivated by two mechanisms: an initial interest if the toy possesses appropriate characteristics (texture, small size) and rapid habituation. Owners should find a number of toys that interest the cat and play with several different toys until the cat’s interest wanes. Cats may also be offered small toys for batting and chasing; boxes or containers to explore; appealing outlets to climb, perch, and scratch; and perhaps an occasional catnip toy (to which 50%–75% of cats respond).

Teaching the basics of reinforcement-based training allows owners to focus on rewarding desirable behaviors (eg, where to eliminate, climb, scratch, or perch). Clicker training ( see Classical Conditioning: Classical Conditioning: In production animals, treatment focuses on group management, environmental or housing modifications, and in some cases removing individual animals out of or to other groups. Specifics are covered... read more ) can be particularly useful to immediately time (mark) desirable behaviors and gradually shape outcomes that more closely approximate the final goal. Punishment should be avoided, because it can cause fear and anxiety toward the owners or fear of handling and petting and, at best, will stop the undesirable behavior only when the owner is present. Provided all of the cat’s needs are adequately met, the best approach to stop repetition of the undesirable behavior can be to prevent access to areas where problems might arise. Another alternative is to teach the cat to avoid the area by making it unpleasant with taste (eg, cayenne pepper), odor (eg, citrus), substrate (eg, upside-down carpet runner, double-sided sticky tape), or perhaps a motion-activated device (eg, alarm, air spray).

Diagnosis and Treatment

Assuming all possible medical causes have been excluded, a thorough history is necessary to diagnose, determine the prognosis, and develop an appropriate treatment program. In cats, especially those with elimination and marking problems, it is particularly important to assess the environment either by visiting the home or having the owners diagram the home so that it can be determined how the environment affects the problem and how it might be modified to improve the situation.

Response substitution (training an alternative desirable behavior) can be a useful approach if the cat is reward trained with food or favored toys to respond to one or more simple commands (eg, come, sit). A leash and harness can be used as an aid in training as well as a way to prevent undesirable behaviors and ensure safety. For fearful behavior, access to the stimuli should be prevented, at least in the short term. For example, if cats are fearful or aggressive with other cats or visitors, confinement away from the stimulus is an essential first step to ensure safety as well as to prevent further aggravation of the problem. This generally involves housing the cat in its own room with litter, toys, bedding, and food. When the cat is calm and comfortable, it might then be possible to gradually reintroduce the cat using favored toys, treats, or food for counterconditioning.

Drugs for fearful behaviors that could be used on an ongoing basis include fluoxetine, paroxetine, or clomipramine; buspirone or other tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) might be an alternative. A benzodiazepine such as alprazolam might be used on an as-needed basis for situational anxiety such as car rides. Because of the range of individual variability in behavioral effects and adverse effects, trials with different benzodiazepines should be done in advance to determine which drug and dose achieves the desired effect and for how long. Caution is necessary, particularly with the use of diazepam, for any indication of anorexia or depression, because rare cases of acute and potentially fatal hepatic dysfunction have been reported. In some situations, a benzodiazepine such as clonazepam might be considered on an ongoing basis for a more immediate anxiety reduction and to enhance appetite for counterconditioning. Natural products including the F3 cheek gland pheromone (Feliway® [available as diffuser or spray], l-theanine (Anxitane®), alpha-casozepine (Zylkene®), and a diet containing both alpha-casozepine and l-tryptophan (Royal Canin Calm Feline™) might also be used alone or adjunctively with drugs or other natural products to help calm, reduce anxiety, or reduce the stress associated with environmental change. The F4 cheek gland pheromone (Felifriend®), associated with social marking (bunting) of cats, is also available as a topical gel in some countries to reduce fear of people or other cats. With intercat aggression, buspirone or a benzodiazepine might increase the confidence of the victim cat during reintroductions. However, anxiolytic drugs could disinhibit and increase aggression.


With housesoiling, the first step is always to exclude medical problems, because any condition that affects urine volume, frequency, control, or ability to access the litter box can contribute to soiling. Evaluating the behavioral history is then the primary process to make the diagnosis, determine the prognosis, and develop a treatment plan. Important aspects of the history include whether the elimination is urine or feces, whether urine deposits are vertical (spraying) or horizontal (soiling), duration and frequency of the problem, signalment and temperament of the soiling cat, when and where the cat eliminates, litter box details (number, placement, cleaning, substrate, size), the cat’s daily routine, and its home environment.

Urine Marking (Spraying):

Spraying is emission of a stream of urine onto vertical surfaces, usually accompanied by elevation and quivering of the tail and in some cases treading of the feet. Marking on horizontal surfaces (eg, owner’s clothing, bedding, or countertops) is less common. Spraying is much more commonly seen in male cats, and neutering will reduce or eliminate it in most cats, although ~10% of neutered males continue to mark. Marking may be due to anxiety, such as might arise with introduction of a new cat; a change in schedule, environment, or family (eg, renovations, new furnishings, new baby, marriage or divorce); or unfamiliar visual, auditory, or olfactory stimuli.

Treatment can include a combination of prevention, environmental modification, behavior modification, and medication. Providing more litter boxes and more litter box locations, cleaning the soiled areas with bacterial or enzymatic cleaners, and cleaning the litter box more frequently may reduce or eliminate marking in some cats. Punishment is contraindicated, because it increases fear and anxiety in an already anxious animal. Unless the stimuli inciting marking or the underlying factors contributing to the marking can be effectively resolved, most cats are likely to require drug therapy with either fluoxetine or clomipramine (buspirone or other SSRIs or TCAs might be an alternative). Feline pheromones in the form of a spray on marked locations or a diffuser in the environment might also effectively reduce marking alone or in combination with drugs.

Inappropriate Elimination:

Soiling on horizontal surfaces with urine, feces, or both, can be a problem in males and females. Cats that consistently return to the same location or substrate may have a location or substrate preference. Cats that do not use their litter for urine, feces, or both may be avoiding the litter itself, the litter box, or its location. A common cause of avoidance is any medical problem that might cause painful elimination, increased frequency, lack of control, or difficulty accessing the litter box. If medical problems have been excluded or treated and the problem persists, the focus should then be on the behavioral history. Avoidance might arise because of aspects of the substrate (texture, depth, scent, cleanliness), box (size, shape, hood), or location that reduce appeal; unpleasant experiences at or near the box (eg, insufficient cleaning, noises, pain due to medical problems); or difficulty in gaining access to the box. Although anxiety may not be an inciting factor for inappropriate elimination, cats may avoid the litter or box if fearful (ie, personality) or when there is conflict between cats in the home (whether active or passive). Although substrate, litter box, and location preferences may arise secondary to avoidance, some cats may actually have a preference for a particular odor, texture, or location.

Treatment should focus on providing a litter, box, and site that is most appealing to the cat; reducing or preventing the use of the soiled location; and resolving the underlying factors contributing to the soiling. Appeal might be improved by identifying and resolving potential deterrents (eg, undesirable location, fear-evoking stimuli such as furnace noise, or limited access such as a shared washroom), adding additional boxes or additional sites, finding a more appealing location for the litter, improving access to the litter (eg, larger box, ease of entry, ease of exit), and finding out which litter (eg, sand, clumping, clay, soft towel, scented) and box type (eg, size, shape, height, covered, self-cleaning) is preferred by offering the cat choices to decide. Access to the soiled location might be prevented by blocking access to the area, or the appeal reduced by using odor counteractants in the soiled area, making the area unpleasant (eg, double-sided sticky tape, upside-down [nubs-up] carpet runner), or changing the function of the area (play, scratching, feeding, sleeping).


Aggression Toward People:

Aggression toward owners may be fear induced or related to play or predation. Cats that bite during petting may have a low tolerance for physical contact, and some cats bite to keep people from approaching or handling them when they are resting, sleeping, or eating (which may be a learned, fear, or social issue). Aggression may be particularly intense if the cat is approached when it is aroused. When the arousal is due to a stimulus to which the cat cannot gain access (eg, another cat outside, loud noise), the cat may redirect its aggression to any person who approaches.

Some cats display abnormal and out-of-context social responses, including aggression, when approached or handled. This may have a genetic component that is compounded by insufficient socialization, lack of adequate maternal care, inadequate early handling, and fear-evoking or traumatic early experiences. However, at the time of presentation, most aggression also has a learned component, because any unpleasant response on the part of the owner (eg, fear, punishment) will cause increased fear, whereas retreat of the owner negatively reinforces the behavior. Aggression toward strangers most often has a fear component.

Aggression Toward Other Cats:

Cats may display aggression toward other cats due to play, predatory behavior, redirected behavior, fear, and perhaps as a status-related behavior in which cats use aggression to retain control of sleeping areas, common areas, or possessions. Ultimately, the relationship that develops between any pair of cats will be affected by learning, because fearful responses by either cat can increase aggression, as will retreat of one of the cats (negative reinforcement). Aggression toward unfamiliar cats is most often a fear response but may have a territorial component.


The first step is to ensure that further injuries are prevented. Avoidance (physical, visual, and preferably olfactory separation of cats that are fighting) is paramount, and early intervention is best. Although some cats will need to be separated at all times until they are calm enough to be reintroduced, if there are particular times or situations when conflicts arise, it might be necessary to separate the cats only at these times. Only after the cats are calm (which can take days to months) can desensitization and counterconditioning with favored rewards begin (ie, play with toys, treats). Desensitization and counterconditioning might first begin with odors by grooming each cat with a brush or towel used on the other, and by feeding each cat separately in a common area on opposite sides of a partition (glass, screen, or solid door) and then in a common area at sufficient distance that the cats can be calm and take food or play with toys. Training one or both cats to wear a leash and harness can help to ensure safety and distance during reintroductions, while a bell on the aggressor can help the victim be aware of its whereabouts. Providing more three-dimensional space, including climbs and perches, and ensuring sufficient resources at sufficient distance to facilitate avoidance can further decrease conflict. Reward training limited to a few selected verbal cues (eg, come, sit, go to your room) can further aid in managing the cats during introductions or in diffusing potentially aggressive situations. Punishment should be avoided, because it increases fear and anxiety in cats. Drugs might also be indicated ( see Treatment of Fears, Phobias, Anxiety, and Aggression Treatment of Fears, Phobias, Anxiety, and Aggression 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... read more ).

Feline Compulsive Disorders

Abnormal repetitive behaviors in cats are derived from normal behaviors such as stalking, chasing, grooming, etc. These may be exacerbated by stress or anxiety such as alterations in relationships with people or other cats, or may be inadvertently aggravated by the owners either reinforcing or punishing the behavior (increasing conflict and anxiety). If these behaviors occur out of context or in a frequency or duration in excess of that needed to accomplish the task, a diagnosis of compulsive disorder should be considered. Medical problems must be excluded, because they can be responsible for many of the same signs. For example, self-mutilation, excessive grooming, and/or self-directed aggression can be due to any condition that might cause neuropathic pain or pruritus such as adverse food reactions, atopic dermatitis, and parasitic hypersensitivity.

Cats that suck, lick, chew, or even ingest non-nutritive substances—including natural materials such as wool or cotton, synthetic fabrics, plastic, rubber, paper, cardboard, and string—may have a compulsive disorder if the problem becomes sufficiently frequent or intense; however, disease processes, in particular those that might affect the GI tract, should first be excluded. Oriental breeds develop pica, particularly sucking of woolen objects, more frequently than other cats. Hallucinatory and locomotory compulsive disorders are less common than in dogs; however, painful conditions and any disease process affecting the neurologic system first need to be excluded.

Cats often improve with modifications to the environment that provide more control and predictability and increased enrichment, combined with medications that augment the amount of brain serotonin such as fluoxetine and clomipramine.


Hyperesthesia may not be a specific disorder but rather a sign of underlying medical or behavioral problems. Most commonly, the skin along the lumbosacral area may twitch or ripple. There may be excessive self-grooming, hissing or biting at the back or flank, and intensive tail wagging. Some cats cry, dash away, and even defecate. These episodes arise when the cat is highly aroused and may be incited by physical contact or external stimuli. A compulsive disorder is a consideration when the intensity, frequency, and duration of these problems is sufficiently severe. However, medical causes such as neuropathic pain, dermatologic conditions, myopathies, and focal seizures can also present with similar signs. Therefore, a therapeutic response trial for neuropathic pain, seizures, pruritus, or compulsive disorders might be part of the diagnostic process.


Fear may arise in cats as a result of genetic factors, lack of sufficient early socialization and exposure, or fear-evoking experiences. The fear may be of unfamiliar people, unfamiliar cats, dogs, noises, or places and situations such as car rides, veterinary visits, and unfamiliar environments. Some cats may also be fearful of familiar people and cats. This may be evidenced as threatening displays and overt aggression (see above) or avoidance, withdrawal and hiding, and possibly spraying.

Treatment should begin with identification and avoidance of any situation, stimulus, approach, or handling that might lead to fear. When the cat is sufficiently calm, gradual improvement might be achieved with desensitization and counterconditioning. Drugs might also be indicated ( see Treatment: Treatment: As with dogs, undesirable behavior might be 1) normal behavior but undesirable for the owners (eg, climbing, scratching, and excessive nocturnal activity); 2) behaviors that fall within the... read more ).

Aging and Cognitive Dysfunction

Aging and younger cats have similar behavior problems; however, the likelihood of a pathophysiologic underlying condition is higher in older cats. Many diseases, including those affecting the CNS, metabolic and endocrine systems (eg, renal disorders, hyperthyroidism), sensory decline, and pain (eg, arthritis), may present with behavioral signs. Once medical problems have been excluded or treated, behavioral therapy may be required. Behavior problems in senior pets may be more difficult to resolve because of a decline in cognitive function, medical problems that cannot be entirely resolved, and drug contraindications or adverse effects.

Cognitive dysfunction syndrome (CDS) is less commonly reported in cats than in dogs. Yet in one study, ~35% of cats >11 yr old displayed at least one sign of CDS, and 50% of cats >15 yr old showed two or more signs. Brain changes are similar to those seen in CDS in dogs ( see Aging and Cognitive Dysfunction Aging and Cognitive Dysfunction 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... read more ). Environmental enrichment and mental stimulation is paramount to prevent and treat CDS. Medications, diets, and supplements might also improve the signs of CDS or slow its progression. Although no drugs or diets are licensed for feline CDS, selegiline and propentofylline have been used off-label. Both S-adenosyl methione and a commercial diet containing antioxidants, arginine, B vitamins, and fish oil have demonstrated improvement in learning and memory in geriatric cats. Cognitive supplements containing antioxidants, vitamins, and phosphatidylserine have also been developed for cats.

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