Definition

• Heterogeneous group of conditions with differing pathologies including compulsive, stereotypic, and neurologic; therefore “abnormal repetitive behaviors” might be used to describe the clinical presentation until a diagnosis is made.
• Can be categorized as locomotor (spinning, tail chasing, circling, fence running, pacing, light/shadow chasing); oral (licking, sucking/mouthing an object/body part [e.g., flank, tail, limb], pica, excessive drinking, “fly biting”); or hallucinatory (“fly biting,” hind end checking, freezing, staring), with or without vocal and affective responses.
• Compulsive disorders are abnormal, repetitive, exaggerated and/or sustained, variable in form and fixated on a goal. They are derived from normal maintenance behaviors such as grooming, predation, and ingestion. Motivational conflict or frustration appears to trigger the behaviors in specific contexts often associated with high arousal; over time, with repeated/sustained conflict, the behavior becomes emancipated from the original trigger stimuli and is displayed in diverse contexts.
• Stereotypies are repetitive behaviors that are unvaried in sequence and have no obvious function or purpose. They may arise in situations of conflict or frustration related to confinement or husbandry practices, when the environment lacks sufficient outlets for the normal behavior repertoire, and with maternal deprivation.

Pathophysiology

• Likely associated with alterations in brain neurotransmitter functions: primarily serotonin; also dopamine, endorphins. Different CDs may preferentially involve different brain regions.
• Abnormal serotonin transmission has been identified as a primary mechanism by which compulsive disorders are induced; stereotypies might be induced by dopaminergic stimulation.

Systems Affected

• Behavioral-fear, anxiety, aggression.
• Cardiovascular-tachycardia.
• Endocrine/Metabolic-HPA axis upregulation.
• Gastrointestinal-inappetence, gastroenteritis, foreign body obstruction
• Hemic/Lymphatic/Immune-stress leukogram
• Musculoskeletal-weight loss, self-injury.
• Respiratory-tachypnea.
• Skin/Exocrine-abrasions/lacerations/; wounds/infections secondary to self-trauma.

Genetics

• Likely genetic predisposition/susceptibility: higher than expected occurrence among first-generation relatives (though manifestations may differ).
• Certain breeds overrepresented for specific CDs.

Incidence/Prevalence

Generally uncommon; more common in certain breeds/families.

Signalment

Signs

Causes

No direct cause

Risk Factors

• Environmental stress (e.g., kenneling-spinning), management, illness, other.
• Owner/environmental reinforcement of the behavior.
• Medical disease, pain, or neuropathy-may increase anxiety or may be primary cause of behavior.
• Sensory abnormalities (e.g., visual deficits) may contribute.

Differential Diagnosis

• Dermatologic disease (e.g., atopy)
• Gastrointestinal disease (e.g., IBD)
• Metabolic/endocrine disease (e.g., Cushing's)
• Neurologic disease (e.g., seizure focus, forebrain neoplasia)
• Orthopedic disease (e.g., DJD)
• Any disorder causing abnormalities of sensation such as dysesthesia, paresthesia, (sensory neuropathy)
• Other problem behaviors: displacement or conflict behaviors, play and attention seeking, and behaviors occurring secondary to lack of stimulation or due to resource restriction (e.g., water restriction-excessive drinking),
• Diagnostics needed to rule out physical causes of behavior, especially self-mutilation.

CBC/Biochemistry/Urinalysis

• Usually within the laboratory's reference range-use for general health screening; prior to drug use.
• Hematocrit, cholesterol, triglyceride increases have been reported.

Other Laboratory Tests

Various; specific to differential diagnoses.

Imaging

• For neurologic differentials, CT and MRI to rule out structural brain disease; altered brain/gray matter volume/density reported in CD.
• Radiography, ultrasound if needed to rule out underlying physical causes.

Diagnostic Procedures

• None specific for CD.
• Indications based on other differentials (e.g., endoscopy, biopsy, echocardiography).

Appropriate Health Care

• Outpatient unless severe self-mutilation/self-injury; hospitalization may exacerbate CD.
• Sedation-stop-gap measure; if needed to stop serious self-mutilation, increases suspicion of underlying physical abnormality.
• Treat associated physical conditions (primary or secondary).
• Combination of environmental modification, behavior modification, and pharmacologic treatment.
• Pharmacologic intervention-implement early; reduction of anxiety facilitates behavioral therapy.
• Environmental modification-reduce stress and anxiety; identify and remove sources (e.g., triggers) and/or begin desensitization and counter-conditioning exercises.
• Punishment-contraindicated; increases anxiety, may worsen behavior and increase patient secrecy.
• Provide structured, consistent interactions, routine, and sufficient exercise, enrichment/mental stimulation appropriate to the species and individual; includes interactive play and reward-based training.
• Behavior modification-teach the patient to relax in a variety of settings; also teach a calm, desirable behavior incompatible with the stereotypic one, coupled to a verbal cue (e.g., for circling, teach to lie down with head and neck outstretched in response to “Head down”). In some cases, a head collar (e.g., Gentle Leader, Halti) left on the dog (when the owner is home) in the problem contexts may allow the owner to use gentle physical guidance along with verbal encouragement/cues to interrupt the behavior and redirect it more effectively. Monitor for situation in which behavior occurs and pre-empt it by engaging the pet in an incompatible activity; if behavior occurs, disrupt immediately, redirect the animal to alternative incompatible activity and reward (food, play, other reinforcer).
• Have clients monitor behaviors via videos and written logs for objective assessment of response to therapy. Improvement may be seen in frequency and/or intensity of bouts. Discussion of a rating scale and how to judge changes may help in assessing response to therapy.
• Bandages, collars, braces, and crates increase distress, do not address the behavioral condition, and may worsen it. If needed to ensure healing, use as briefly as possible.

Activity

Environmental enrichment

Diet

N/A

Client Education

• Cure is unlikely; usually requires life-long management.
• Teach client to recognize all body language/behaviors reflecting anxiety.

Surgical Considerations

Tail/limb mutilation: avoid amputation; it is unlikely to resolve the CD.

Drug(s) Of Choice

• SSRIs and TCAs-effects are via CNS serotonin effects.
• Generally treat at low end of dose range for 4–6 weeks; gradually increase dosage if ineffective and no adverse events.
• SSRIs: fluoxetine 1–2 mg/kg q24h; sertraline 1–3 mg/kg q24h; paroxetine 1–2 mg/kg q24h.
• TCAs: clomipramine is most serotonergic (most effective, fewest side effects)-2–3 mg/kg q12h.
• If symptoms resolve, continue medication for >1 month, then reduce dose no faster than 25% every two weeks. Recurrence common.

Contraindications

• Hepatic or renal compromise-medications metabolized by these organs.
• Cardiac conduction anomalies-TCAs.
• Use extreme care combining serotonergic drugs (e.g., SSRI with tramadol); risk of serotonin syndrome (potentially fatal).
• Do not use SSRIs or TCAs within 2 weeks of MAOIs (e.g., selegiline, amitraz).

Precautions

• Use of listed medications for CD is extra- or off-label.
• TCA overdose-cardiac conduction disturbances.
• TCA/SSRI overdose-serotonin syndrome.
• Most common side effects of SSRIs and TCAs: lethargy, appetite change; less common: increased anxiety/reactivity, vomiting/diarrhea; severe side effects may necessitate drug discontinuation.

Possible Interactions

SSRIs competitively inhibit CYP450 enzymes: may increase warfarin, many TCAs, some benzodiazepines and anticonvulsants, other medications; check compatibility and adjust dosage if necessary.

Alternative Drug(s)

• Synthetic pheromones (Adaptil), l-theanine or alpha-casozepine may reduce anxiety (see label for dosing).
• Second-line TCAs, e.g., amitriptyline 1–6 mg/kg q12h.
• Selegiline (MAOI) 0.5–1 mg/kg q24h: may be effective in some cases.
• Memantine (NMDA receptor antagonist) 0.3–1 mg/kg q12h.
• Narcotic antagonists (e.g., naltrexone, naloxone) may be effective but not a practical therapeutic option. Antipsychotics (e.g., thioridazine, haloperidol) not recommended risk of adverse effects, efficacy undocumented.

Patient Monitoring

• CBC, biochemistry, T₄ (TCAs may artificially lower) and urinalysis-semiannually to yearly if chronic treatment; adjust dosages accordingly.
• Medications may take 8–12 weeks or longer to affect CDs; first sign of efficacy may be change in bout duration/frequency.
• Relapses common during stressful situations; manage with increased intensity of behavior modification, addition of short-term, shorter-acting anxiolytics (e.g., benzodiazepines).

Prevention/Avoidance

Monitor animals with affected relatives; early recognition and intervention.

Possible Complications

Dermatologic/musculoskeletal injury; gastrointestinal disorders.

Expected Course and Prognosis

• Untreated CDs almost always progress.
• >50% reduction in CD in approximately two-thirds of cases with appropriate medication and behavioral and environmental modification.

Associated Conditions

Various; specific to type of CD.

Pregnancy/Fertility/Breeding

• Listed medications not evaluated/contraindicated in pregnant animals; avoid use.
• Do not breed affected animals.

Synonyms

Obsessive-compulsive disorder

See Also

Acral Lick Dermatitis

Abbreviations

• CD = compulsive disorder
• CNS = central nervous system
• CT = computed tomography
• CYP450 = cytochrome P450
• DJD = degenerative joint disease
• HPA = hypothalamic-pituitary-adrenal
• IBD = inflammatory bowel disease
• MAOI = monoamine oxidase inhibitor
• MRI = magnetic resonance imaging
• NMDA = N-methyl-D-aspartate
• SSRI = selective serotonin reuptake inhibitor
• T₄ = thyroxine
• TCA = tricyclic antidepressant

Client Education Handout Available Online