Role of Drugs in Behavioural Therapy

Overview

In most cases of feline behaviour problems behavioural modification alone is enough to resolve the problem. Anxiety, fear and ‘phobia’ can be treated effectively using conventional methods such as desensitisation and counter-conditioning. The use of drugs for behavioural conditions should be combined with behavioural modification and not used as a sole solution for the problem.

When used in conjunction with conventional methods drugs are most effective and any underlying medical cause for problem behaviours should first be ruled out before any pharmacological intervention (Overall, K.L., 2003. Medical differentials with potential behavioral manifestations. Veterinary Clinics of North America: Small Animal Practice 33, 213–229.)

Depression, anxiety, fear and phobia may be associated with genuine long-lasting neurotransmitter and synaptic changes in the CNS, but these changes are often reversible through new learning.

An example of a typical approach to fear using behavioural modification would be:

• Identify all fear provoking stimuli
• Identify the threshold for the fear response [e.g. distance from target]
• Establish a gradient of stimuli [distance, appearance of person etc]. This should be used to understand approach-avoidance.
• Control the pet’s environment [prevent exposure in uncontrolled situations]
• Desensitisation and counter-conditioning: desensitise using gradually increasing exposure to fear-eliciting stimulus at a level below which fear is evoked, use counter-conditioning to replace fear with another incompatible emotional response to the same stimulus. Thus downwardly shifting the hypothetical avoidance line on the Miller diagram.

A similar approach is used for anxious behaviour:

• Identify context and conditions of anxiety.
• Identify cues that animal uses as a predictor of such contexts/conditions [owner clothing, preparations for departure etc in the case of separation anxiety].
• Desensitise, counter-condition and reduce predictive value of cues that cause anxiety.
• Train some specific commands and responses that allow the animal to be instructed to relax on cue.
• Teach the animal to relax in those contexts where anxiety has occurred.

In the human behaviour field many of these problems are successfully treated without using drugs. For example, cognitive and behavioural approaches are more successful for treating fears and phobias in man. Depression and anxiety problems are only partially resolvable using drugs. In the veterinary behaviour field there are only a very few drugs which have been scrupulously tested under controlled trials. For the majority of other medications there is minimal available data and information is extrapolated from use in the field of human behaviour. When using drugs which are not licensed for veterinary use it is important to consider that drug metabolism and effects vary between species. (Merck)

Use of Drugs in Animals

In some cases medication can be a useful adjunct to behavioural modification techniques, examples of when the use of a drug in an animal for behavioural problems include:

• When fear or anxiety is great:

• Making therapy difficult or dangerous, bearing in mind the risk of disinhibition.
• Where conditions eliciting fear or anxiety are unavoidable in normal life.
• Where the animal is suffering as a result of chronic anxiety or repeated fearful experiences.

• When the prognosis is likely to be improved:

• Condition is longstanding or severe and therefore less likely to respond to behaviour modification.
• Where distraction is difficult [e.g. severe stereotypy/compulsion].
• If speed of recovery is critical [threat of legal action, eviction etc].

When considering whether to incorporate psychoactive drugs into a treatment program for problem behaviour there are several conditions which should be met:

1. A sensible diagnosis should be arrived at.
2. The clinician should have knowledge of the neurochemistry relating to the condition.
3. The clinician should have an awareness of the supposed mechanism of action of the selected drug.
4. The clinician must have a clear understanding of any potential side effects.
5. Both the clinician and owner need to have a clear idea of how the selected medication will change the behavioural pattern which is a problem. Owners must be informed of potential side effects and warn the clinician if there is even the slightest problem. As medication for behavioural conditions is often long-term owner awareness and compliance is very important.

These guidelines are important to ensure the correct use of drugs within the behavioural field as administration of medication is always long-term in comparison to most other drug use and they help the owner take-part in the process of evaluation as to the effectiveness of the drug prescribed. (Overall, K.L., 2004. Paradigms for pharmacologic use as a treatment component in feline behavioral medicine. Journal of Feline Medicine and Surgery 6, 29-42.)

Before any drug is prescribed a comprehensive behavioural and medical history should be compiled. In older animals, those suffering from cardiac or endocrine disorders as well animals which are already on treatments for any existing conditions extreme care should be taken. All animals should undergo a complete physical examination as well blood tests. For a cat a complete blood count, serum biochemistry panel and urinalysis, ideally with culture and sensitivity form a complete laboratory work up (Overall, K.L., 2003. Medical differentials with potential behavioural manifestations. Veterinary Clinics of North America: Small Animal Practice 33, 213–229.). In addition in older cats thyroid levels should be tested and if cardiac disease is a worry a lead II ECG should be performed to exclude the existence of cardiomyopathy. This also provides a baseline for cardiac side effects of medications to be measured against. (Nattal, S., Mittleman, M., 1984. Treatment of ventricular tachyarrhythmias resulting from amitriptyline toxicity in dogs. Journal of Pharmacology and Experimental Therapeutics 231, 430–435).