Hyperkinesis: A Case Study Of Drug Treatment

The first controlled studies of hyperkinesis in dogs were an outgrowth of a long-term attempt to develop animal models of psychopathology. Dogs were chosen for these studies for several reasons, primarily because there were many carefully bred animals available. This allowed an evaluation of genetic strains in certain breeds. Also, dogs are the only domestic animal with a variety of emotional responses comparable to those seen in people: they worry about things not essential to their survival.
 
In studies designed to evaluate responses to stress, some dogs did not respond to Pavlovian conditioning. Positive reinforcement, negative reinforcement and tranquilizers were all tried, but nothing worked. Typically such dogs would be eliminated from the study, but because the researchers were interested in the interaction of genetics and psychological environment, they were curious about dogs that appeared unwilling to be studied. Eventually the researcher decided they were dealing with the equivalent of a hyperkinetic children. On that basis, amphetamines were given, and the tentative diagnosis proved correct.

The first model of hyperkinesis in a dog was Jackson, a Cocker-Beagle mix whose usual response to any approach was to snap, snarl, growl or, if possible, bite. Many experienced, gentle dog handlers were bitten, until eventually laboratory personnel refused to approach the dog. Jackson responded the same to other dogs. He viciously attacked any dog without hesitation, even friendly and docile animals. He refused to submit to Pavlovian conditioning, and destroyed laboratory equipment in his rages.

Because depressants were not effective against Jackson's abnormally hyperactive and vicious behavior, it was suspected that hyperkinesis may have been involved. On this assumption, the dog was given amphetamine orally. Within 2 hours, Jackson's personality changed to complete docility. He whimpered as if he wanted to be petted. When petting was stopped, he begged for more. He became nonviolent, even submissive, toward the same dog he had attacked earlier. Jackson appeared to be perplexed and unsure of what to do.

When placed in the Pavlovian experimental stand after medication, Jackson responded normally and learned rapidly, indicating that his previous failure was not a result of mental retardation, but rather a secondary effect of his behavior problem. After 6 weeks of drug-facilitated psychosocial therapy, medication could be withdrawn without reappearance of aggression, but hyperkinesis reappeared in low-threat situations. Aggression was apparently trained out by the drug-facilitated social interaction and conditioning experiments, indicating that what is learned under the influence of amphetamines is retained later.

After 2 more months of psycho-social therapy using amphetamines, Jackson's non-medicated hyperkinesis was also reduced. Because he was between 1 1/2 and 2 years old at the time of the experiments, maturation could have been associated with the cure; however, 6 older hyperkinetic dogs did not outgrow their abnormal behavior patterns.