Feline compulsive behaviors are based on natural behaviors that are somehow frustrated by management practices and/or restrictive environments. Compulsive behaviors may initially be expressed as displacement behaviors. For example, when a cat is torn between responding with aggression or running away, it may displace into a seemingly unrelated behavior, such as self-grooming, as a way of reducing emotional tension. If exposure to the anxiety-provoking stimulus continues, the cat may express the behavior repetitively and, finally, out of context.
In the end-stage condition, even when the behavior has adverse consequences for the cat (i.e. pain), it will continue to engage in the behavior. The level of stimulation required to trigger the behavior decreases over time so that the behavior occurs in response to any level of arousal. Certain breeds seem prone to compulsive disorders, so genetic influences are likely involved. Genetics may determine which individuals display compulsive behaviors and what those compulsions are.
The most common compulsive behaviors exhibited by cats include wool sucking (or fabric eating), over-grooming/hair-barbering or hair-pulling (psychogenic alopecia), and feline hyperesthesia. Oral behaviors such as wool sucking and psychogenic alopecia are the most prevalent feline compulsive disorders.
"Wool sucking" refers to the repetitive, inappropriate sucking and chewing on fabric, usually woolen, synthetics or cotton substrates (such as sweaters, blankets or carpets). Some cats even suck on or ingest plastic substrates.
The condition resembles displaced nursing behavior and may be the feline equivalent of thumb sucking. Wool sucking may start as a nursing behavior directed toward the coat of the mother or some other cat. Such misdirected nursing may extend to other fuzzy material. As the cat matures, sucking may progress to pica (consumption of inedible material) and the range of materials ingested may broaden to include a variety of fabrics and other inappropriate items, such as shower curtains, rubber bands, shoe laces, and plastic bags.
The damage inflicted can be quite extensive and costly. Worse, the behavior can pose health risks for the cat, including intestinal blockage. The onset of wool sucking is usually observed at any time after weaning, especially during the first year of life, frequently before 6 months of age. Several predisposing factors have been suggested for this behavior, including genetic factors favoring persistent oral behavior following weaning, early weaning itself, and inadequate environmental or social stimulation (feline separation anxiety).
Medical conditions that can trigger abnormal ingestion of inappropriate material include hunger, nutritional deficiencies, anemia, diabetes, and tumors. Wool sucking is seen predominantly in oriental breeds, although other purebreds and cats of mixed origin as well as domestic long- and shorthairs may also exhibit this condition. Siamese cats appear particularly prone to the condition and account for about 50 percent of all affected cats.
Compulsive wool sucking seems to occur in breeds that are more anxious and more active.
Excessive grooming is called psychogenic alopecia. Cats normally groom as a displacement behavior when momentarily stressed. In some cases, the frequency and duration of grooming lasts longer than it should.
In susceptible animals exposed to chronic stress, grooming may be performed out of the normal context. Such grooming is repetitive, excessive and inappropriate in frequency and intensity. Excessive self-licking and chewing causes hair shafts to become sheared, leaving stubble.
Some cats that engage in the behavior more aggressively actually bite and pull out patches of hair from their coat. Hair pulling and chewing may result in skin wounds and ulceration. Hair loss is typically noted on areas easily accessible to the cat (abdomen, flank, chest, and legs). A stressful change in the environment often coincides with the onset of the behavior. Other anxiety-related behaviors, such as hiding, anorexia, avoidance, may also be observed.
Medical causes should be ruled out before a diagnosis of psychogenic alopecia can be made. The most common medical look-alike condition is that of skin allergy, caused by hypersensitivity to parasites, food, dust, pollen or mold. If a trial dose of corticosteroids controls excess grooming, the condition is probably medical and not psychogenic in origin.
Other medical conditions causing discomfort can cause excessive grooming: e.g. cystitis, inflammation of anal sacs, hyperthyroidism. Even if a medical condition triggers repetitive licking, a susceptible cat may continue to groom excessively even after the medical problem has been resolved.
In general, females appear to be more commonly affected than males. Psychogenic alopecia may occur in any age of cat but tends to arise most often around puberty.
Feline hyperesthesia is a state of abnormally increased sensitivity to stimuli. It is a complicated behavioral condition with some features that appear compulsive and others that appear frankly neurological.