Feline Compulsive Disorders

  These are normal behaviors that have been carried to such an extreme that they are damaging to the cat (self-injurious behavior or SIB), or disturbing the human animal bond.  The innate component of behaviors is encoded in regions of the limbic system and hypothalamus, and the motor aspect facilitated from the limbic system to the basal ganglia.  The frontal cortex can activate or inhibit any given behavior depending upon the circumstances.  Normal behaviors such as grooming are triggered when they are required and the situation permits.  Anyone who has watched a cat is familiar with displacement behavior.  The cat is faced with a dilemma requiring one of two or more conflicting behaviors that are virtually indistinguishable in their desirability - perhaps to run and hide, or go and explore something new and strange in their environment.  In response the cat indulges in a behavior unrelated to and precluding either of the conflicted behaviors – such as licking its paw.  It is theorized that the neutralizing effect of the two conflicting behaviors disinhibits the displacement behavior.  If the conflict is sustained then so is the tendency to perform the displacement behavior, which can then become ingrained.  Once this has happened the displacement behavior will persist even after the conflict has been resolved resulting in a compulsive behavior sometimes known as a stereotypy.  Besides grooming, other hard-wired behaviors can also become compulsive, including predatory  (both appetitive and consummatory components), ingestive, locomotive, sleep, and maternal and sexual behaviors.   The form of the compulsive behavior is generally species dependent, but is also dictated by the experiences of and outside influences on the animal.  In general, while injury may result from these behaviors it is incidental not purposeful.

  The successful treatment of OCDs has pointed to the involvement of three main neurotransmitter systems - dopaminergic, serotonergic and opiate.   Recently, it has been shown that nitric oxide synthetase can have a significant effect on these behaviors, which suggests that nitric oxide is also involved in regulation of some of these conditions.  OCD signs are exacerbated by treatment with dopamine agonists.  In humans and rodents compulsive behaviors can be induced by large doses of dopaminergic drugs - amphetamines, apomorphine.  Dopamine injected into the caudate nucleus of the cat also induces stereotypic behavior.  Unfortunately, most compulsive behaviors do not respond to doses of dopamine antagonists - haloperidol, acepromazine - at doses that do not also induce sedation.  The newer, atypical neuroleptics such as clozapine and risperidone may be more effective, although they have only been tried in a very limited number of cases to date.  Many OCDs both in animals and humans respond positively to treatment with SSRIs.  Serotonin deregulation in the dorsal raphe nucleus or its targets in the basal ganglia and cortex is thought to be important in the propagation of many OCDs.  Opioid antagonists - nalmefene, naltrexone, naloxone and hydrocodone - have also proved effective in treating some animal and human OCDs.  Opioid receptors are found in close association with dopaminergic and serotonergic neurons in the limbic system, hypothalamus, striatum and periaqueductal gray matter.  Opioids facilitate dopaminergic effector systems while serotonin acts as an antagonist.  It has been suggested that the performance of stereotypic behaviors may stimulate the release of endorphins and enkephalins centrally, thereby rewarding the animal for its behavior and reducing the tension it was experiencing.  Over time, the animal performs the behavior in order to give itself a high even when it is not stressed.  Opioid antagonists have proven to have the greatest effect in cribbing in horses, and a lesser effect in other oral behaviors such as feline wool sucking and psychogenic alopecia.   OCDs do not generally resolve over time, and it is likely that, even with environmental enrichment, the cat will be on medication for the rest of its life, or relapse completely if the drugs are withdrawn.

  Human and animal compulsive disorders have one common characteristic - no single drug treatment is effective in more than 60% of those affected.  Augmentation with other types of drug may be helpful in the other 40%.  The same behavior may result from reduced serotonergic activity in one patient and increased dopaminergic or opioid activity in another, although the presentation appears identical.  In many of these disorders heredity seems to play a role equally as or even more important than environment.  This seems to be the case in wool sucking.  The duration of the disorder can also influence the outcome of treatment.  In general, pharmacological intervention is usually required to treat compulsive disorders, but environmental enrichment and modification should not be overlooked.  Boredom, attention-seeking behavior, separation anxiety and other stressors have all been implicated in the pathogenesis of stereotypies.  Neurological disease and tick borne pathogens should be ruled out as causes for some.

  In general, cats are more likely to display biting/chewing behaviors, while dogs are more likely to lick.  Punishment and attempts to stop the behavior are not effective.  The animal may stop temporarily, but resume in another location away from the owner.  In some cases the animal will respond with aggression to the owner’s attempts at interrupting.

Feline psychogenic alopecia

  This is a stress-linked self-grooming behavior that appears to closely resemble trichotillomania (tearing out hair) in humans.  The cat’s excessive licking and plucking pulls out hair in handfuls and leads to large areas of depilation particularly over the limbs, flanks and abdomen.  It is more likely to occur in cats that are subordinate and friendly, and like most OCDs seems more common in the oriental breeds.  Many cats start before they are a year old, although onset can be at any age.  Clinically other dermatological conditions, especially allergy and food hypersensitivity, should be ruled out.  (If the cat responds positively to steroids it wasn’t psychogenic alopecia).  However, the grooming can start as the result of a dermatological condition, but persists as a compulsive disorder after the underlying cause has been resolved.  More typical stressors seem to be the arrival of new cats in the household, the loss of old buddies that have died, or a change in schedule that requires the prolonged absence of an owner.  In general, the drug we will first recommend, once dermatological causes have been ruled out, is clomipramine.  However, this or fluoxetine do have the undesirable side effect in some cats of turning them into recluses.  Buspirone appears to be somewhat less effective in treating the stereotypy, but usually produces marked improvement, and as an additional bonus tends to make cats more friendly and out-going.

  Part of a cat’s grooming includes licking the nose and lips.  This can develop into a compulsive behavior too, resulting in the development of eosinophilic (rodent ulcers) or lip granulomas respectively.  Some cats progress to sucking and chewing on the hair, as well as simply tearing it out.  Others may groom their owner or another animal excessively rather than or in addition to themselves.  A yet-to-be-registered breed of cats called the Ohos Azules have a propensity for grooming their owner’s hair, and will persist day and night in their appointed behavior.  This behavior appears to be inherited as a recessive trait.  In another rare breed, the Singapura, this also seems to be the case with psychogenic alopecia.  Some Munchkin cats, an achondroplastic breed, exhibit compulsive hoarding of jewelry and other small objects, and again the trait is recessive.  

Feline hyperesthesia syndrome

This disease goes by a great number of names – as well as feline hyperesthesia syndrome, it may also be referred to as rolling skin disease, neurodermatitis, neuritis, feline psychomotor epilepsy and pruritic dermatitis of Siamese cats.  Despite the last name, the condition has been reported in a number of different purebreds as well as domestic long and shorthaired cats.  The condition usually first appears when cats are between 1 and 5 years of age, and occurs equally in both sexes.  Attacks may occur more often in the evening and morning, but are not seasonal.  In some cats the condition can be induced by petting or stroking them along the spine - hence the term hyperesthesia.  The observed behaviors occur in all cats, but are taken to extremes in the cat with feline hyperesthesia.  The skin over the lumbar region ripples, the cat looks at its tail, which may be held stiffly erect.  The cat then starts to growl and attack its tail so aggressively that it may require amputation.  (This is not curative, and the cat may proceed to attack the stump or tail head.)  Cats may also attack the flanks or pelvis.    They are often very restless and vocal.  Attacks and pacing may be interspersed with periods of violent licking of the forelegs, base of the tail and chewing of the claws. Cats may rush around attacking objects and people indiscriminately.  In contrast, cats that are normally aggressive may become unusually affectionate during bouts of hyperesthesia.  Pupils are dilated and the eyes are glassy.  Owners often describe their cats as being bewitched or hallucinating.  A similarity to human schizophrenia has also been noted.  Less commonly, definite prodromal signs may precede frank seizures, and some cats exhibit uncontrolled urination and defecation.  Between attacks cats generally appear to be normal.  Attacks can range in frequency from almost constant to relatively rare.  Cats may become hyperthermic, probably as a result of increased muscular activity during and right after episodes, but there are no associated abnormalities on blood work.  EEGs may show abnormal slow waves, dysrhythmias and spike discharges.

  The cause of feline hyperesthesia syndrome is unclear.  It has been treated successfully in some cases as a partial seizure disorder with phenobarbital (1-3mg/kg q 8h or 2-5mg/kg q12h) or primidone (0.5-3.0mg/kg q 8, q 12 or q 24h as needed).  In other cats, this approach has had no effect.  Some cases that had either failed to respond to phenobarbital or for which no other treatment had been attempted have been controlled  using serotonin reuptake inhibitors (clomipramine 0.5 - 1 mg/kg q 24h or fluoxetine 0.5mg/kg q 24h).

  The primary rule out for feline hyperesthesia is pansteatitis resulting from Vitamin E deficiency.  This condition results in the deposition of a yellow pigment in fat cells that become inflamed and undergo necrosis.  This process occurring in the subcutaneous fat layer causes skin hypersensitivity.  Cats fed primarily canned red-meat tuna or small amounts of other types of fish may exhibit this syndrome.

  Case: Oscar was a 4.5year old, 13lb, castrated male, domestic short hair, inside-outside cat.  He had been spraying urine in the house for about a year.  For a few months prior to presentation he had begun to attack the tip of his tail viciously and had bitten through to the bone.  Skin rippling preceded tail chasing.  Oscar held his tail stiff, twitching the end, he would then start to hiss at the tail before he launched his attack.  Sometimes he would also attack his flanks and or he would chew hard on his claws.  Sometimes he would attack the owner, particularly if she tried to stop his self-mutilation.  Oscar was receiving 5mg of buspirone q 24h.  This might have reduced his urine spraying a little.  However, it is far less than the 10-20mg q 12h usually recommended for treating a cat of Oscar’s size.  Buspirone was withdrawn and Oscar was started on a seventh of a 20mg capsule of fluoxetine q 24h.  I felt that the new therapy would address both his spraying and feline hyperesthesia.  Initially, Oscar’s spraying seemed to increase; this was attributed to withdrawal of the buspirone while fluoxetine levels were being established.  Spraying then rapidly diminished and was eliminated when his dose of fluoxetine was increased to 5mg q 24h one month after treatment was initiated.  Tail chasing became more playful and less vicious.  The owner noticed that Oscar was more likely to engage in this behavior if it was too wet or snowy for him to go outside.  Introducing a cat dancer toy also reduced aggressive attacks on the tail.  After the dose of fluoxetine was increased, tail chasing virtually disappeared.  When it did occur it was not preceded by skin rippling and seemed to represent grooming or playful behavior only.  The cat never displayed aggression to his owner again after treatment had been initiated.

Tail chasing

 Cats as well as dogs can compulsively chase their tails to the point of inflicting damage, and even necessitating amputation, which is non-curative.  The use of E-collars may redirect the animal’s attention to another part of the body that it can reach.  In general, this is viewed as a compulsive hunting behavior.

Substrate sucking

  Traditionally described as wool sucking, cats can chose any substrate for their attentions, although wool, cotton, acrylic and interestingly plastic are those most frequently seen.  (Plastic may seem unusual in that cats generally avoid the material, and placing plastic sheets in or under litter boxes has been implicated in many cats choosing a different toilet area.)  The oriental cats, particularly Siamese are most frequently diagnosed with this problem - in one study 55% of 152 cats were Siamese, 28% Burmese, and 11% were oriental crossbreeds.  93% started on wool and many moved on to other materials, 64% ate cotton and 54% synthetics.  In general cats start by sucking their own or another cat’s fur and mouthing it into wet tufts.  Some will attempt to nurse on other cats or the family dog.  They may then start to suck and knead on woolen (or other substrate) articles.  The attention some cats show their owners’ hair may also be a variation of this.  Items chosen run a complete gamut - blankets, sweaters, socks, exercise clothing, underwear, shoelaces, sneakers, shower curtains, plastic bags etc.  Mouthing and chewing can also lead to ingestion, and the risk of the cat’s g/i tract becoming blocked.

  Because of the similarities between this behavior and suckling in kittens, it has been suggested that the problem arises because kittens are weaned much earlier in captivity than in the free roaming state, where they often nurse until they are 6 months old.  Neoteny of the oriental breeds has also been cited as a cause; these breeds apparently need to nurse for longer than domestic short and long hairs.   

  It has been suggested that there are actually two behaviors being observed.  Some cats chew rather than suck, and their behavior is likened to that of feral or hunting cats that are chewing on their prey.  Providing cats that indulge in this form with uncooked chicken bones with remnants of residual flesh has been suggested as a more appropriate outlet for their needs.  In some cases, introducing a high fiber diet has proven effective in stopping substrate sucking, although the idea that cats become hooked on the behavior to increase dietary fiber seems unlikely.