Aggression: Triggers, Flashpoints, and Diagnoses
Karen L. Overall, MA, VMD, PhD, DACVB, ABS Certified Applied Animal Behaviorist
The association between anxiety and aggression: Canine aggression is the most common behavioral problem seen in dogs visiting behavioral practices and is the most dangerous one seen in pet dogs.
Overview of dominance aggression: The necessary condition for canine dominance aggression include: abnormal, inappropriate, out-of-context aggression (threat, challenge, or attack) consistently exhibited by dogs towards people under any circumstance involving passive or active control of the dog's behavior or the dog's access to the behavior. The sufficient condition for this diagnosis to be made include an intensification of any aggressive response from the dog upon any passive or active correction or interruption of the dog's behavior or the dog's access to the behavior . This is a very discrete definition of dominance aggression and has the advantage of not coupling the challenge to food (food related aggression), toys (possessive aggression), or space (territorial aggression). These aggressions can all be correlates of dominance aggression and when associated with it may be indicative of a more severe situation. The sentinel issues in the diagnostic criteria are control and access -- most of the problems with diagnosing the condition arise from people's misunderstanding of canine social systems, canine signaling, and canine anxieties associated with uncertainly about contextually appropriate responses.
The diagnosis of dominance aggression cannot be made on the basis of a one-time event. Once the dig begins to show signs of this problem they will become more visible and consistent permitting the diagnosis to be made. Data on early signs, patterns of change with experience, and changes in intensity are lacking. Note that the necessary and sufficient conditions are radically different from the common descriptions of dominance aggression that specify that the dog will often react to being pushed on, to being corrected with a leash, or to being pushed from a sofa or a person. The number of situations in which the dog reacts inappropriately or the intensity with which he or she reacts do not affect the necessary and sufficient conditions, although these factors may affect ability to treat the condition, prognosis, and risk to people.
Implicit in this diagnosis is that, unless explicitly stated, is that there is no known underlying physical or physiological reason for the behavioral problem and that physical and physiological "causes" have been ruled out. It is also important to remember that this type of classification represents diagnoses of problem behaviors, not just descriptions of a behavioral event (i.e., dominance aggression can ONLY be a diagnosis for an abnormal behavior, but interdog aggression can be both a diagnosis and description).
Dominance aggression is a description for a complex of multi-factorial disorders. Because of the association with social contexts, dominance aggression (like all other aggression) is probably representative of a canine anxiety disorder. Dogs demonstrating dominance aggression can be divided into two broad groups: (1) those who have no doubt that they are in control and can compel their clients to do their bidding), and (2) those who are unsure of their social role and use the aggressive behaviors to deform the social system to get much needed information about what is expected of them. They define their social and behavioral boundaries using the response to their aggression. This is analogous to teenage children with behavioral disorders who are disruptive, and sometimes aggressive. These dogs appear to be less sure of their relative hierarchical status and to express more ambiguity in their vocal and physical responses about the intensity of their aggression. The aggression is not applied equally to all humans in the second class of dominance aggression because the dog responds to the social environment in a differential manner based on individual social interactions. A retrospective analysis of the dominantly aggressive dogs seen at the Behavior Clinic at VHUP since 1987 revealed that the vast majority of these dogs also exhibited attention seeking behavior. These are dogs that are very needy and are constantly setting people up to defer to them, not simply because they have an abnormal urge to control, but also because this is the only mechanism they have for getting information about their role in the social environment. It should be implicit that this need for information about their role in the environment has less to do with that dog's particular social environment than it has to do with an inherent abnormality. Response to anti-anxiety medication supports this categorization: dogs in the second group do well with ancillary anxiolytics (e.g., amitriptyline) to help with their behavior modification. These two behavioral profiles also help to explain the different human groups that may be victimized by dogs exhibiting these different forms of dominance aggression.
Role of Hormonal Facilitation: The role of hormones in canine aggression has been discussed largely on the basis of correlational data. Most dominantly aggressive dogs are male. Testosterone acts as a behavior modulator. It makes dogs react more intensely. When an intact dog decides to react to something, he reacts more quickly, with greater intensity, and for a longer period of time. Castration decreases aggression in about 2/3 of the cases involving interdog aggression; however, few data exist for any effect on other types of aggression. Male dimorphic aggressions may be disproportionately represented in such studies. One study has made a good first attempt to quantify behavioral influences of early neutering for dogs both with and without a history of behavioral problems. In a preliminary study examining the effects of neutering on the behavior of dogs less than 6 months of age and 12 months of age or older, one group stood out. Females younger than 6 months of age who were already showing signs of dominance aggression became more aggressive post-ovariohysterectomy (Gadj = 5.95, p # 0.05; my analysis). All other statistical comparisons indicated that aggression either did not change, or decreased with age, regardless of hormonal status, although a slight trend towards increasing aggression was noted for bitches as they became socially mature. Data from VHUP indicate that androgens may be implicated in dominance aggression in females. Although less common in males that in females, when dominance aggression does occur in females, the patients tend to be very young (less than 1 year and usually less than 6 months of age compared with 18-36 months of age for males), present with profound aggression that gets rapidly worse, and may have delayed heat cycles. This form of dominance aggression may not be the same as dominance aggression that appears at social maturity, nor may it have the same catalogue of behaviors seen in dominance aggression that appears at social maturity. The concept of multi-factorial causality is only recently being accepted in medicine. This is another area that warrants better description of the symptomology, more specific diagnoses, and more experimental research.
Prognosticators: Prognosis is worse with: a. the earlier the age of onset, b. the longer the duration, c. the more intense or frequent the bouts of aggression, especially if intensity or frequency is increasing with time.
Cure v. control: Aggression, like diabetes, is not curable, but, may be controllable in the majority of cases. In a retrospective analysis of prognosticators of aggressive cases seen at VHUP, client compliance and extent of effort was the single best determinant of success. A dog that both the behavioral specialist and the owners feel is greatly improved and with whom the owners are comfortable and content to live is a success. Because of the potential danger and liability involved, everyone involved in treating an aggressive animal must be realistic about what to expect, and what they want and can handle. Requirements vary from one household to the next. A dog that could live safely and non-aggressively in a childless household may not be able to do so safely in one with children. It would be unfair and perhaps, dangerous to guarantee absolute reliability in any dog, including those treated for aggression. A dog could appear "cured", but relapse if clients cease to reinforce the dog's appropriate behaviors. In the case of dominantly aggressive dogs, such reinforcement may mean never letting the dog succeed with subtle, non-aggressive signs of control, like pushing.
Until clients can seek qualified help, they should avoid circumstances known to precipitate the specific aggression. With therapy it may be possible to desensitize the dog to circumstances to which it reacts aggressively, but avoidance is key in minimizing danger.
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Diagnostic Correlates of Aggressive Signs: Canine Aggression Screen
NR=no reaction; SL=snarl/lift lip; BG=bark/growl; SB=snap/bite; NA=not applicable
Please note if the reaction is consistent or only to one person or in one circumstance. Also note if the dog has been worsening in one category.
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