Anthony L Podberscek
Aggression in dogs is one of the most common problems treated by behaviour counsellors, and can be categorized in a number of ways, for example, dominance-related, predatory, territorial, possessive and interdog aggression. One type of aggression which is difficult to categorize is rage syndrome. The difficulty arises from our having little knowledge of what actually causes it. To this end, it is usually placed in a category of aggression known as ‘idiopathic aggression’, which basically means aggression for which there is no known or understood cause. In this chapter we’ll look at the current state of knowledge on this perplexing form of aggression.
Rage syndrome refers to sudden, unpredictable, unprovoked and uncontrollable violent aggression towards a person, other animal or object. The term became popular during the early 1980s, when there was a series of newspaper articles (e.g. ‘Top Dogs Turn Nasty’, The Sunday Times, 1981) and magazine articles (eg. ‘Solid Cockers Condemned’, Dog World, 1981) on aggression in English Cocker Spaniels, in particular those of solid coat colour (e.g. red/golden, black). These were in response to a scientific paper written by animal behaviourist Roger Mugford on the types of aggression in English Cocker Spaniels he treated at his clinic. Indeed, the publicity was such that rage syndrome became synonymous with this breed, leading some to call it ‘Cocker rage syndrome’. And this association has since been further enhanced in the media, including a feature article (along with cover photo) in Dogs Today in October, 1992: ‘Cocker Rage Syndrome: Madness or Make-Believe?’ People have even suggested that there are references to a Cocker ‘raging’ in 19th-century England: that Elizabeth Barrett-Browning, in her letters to Robert Browning, makes references to rage-like behaviour in her male, golden Cocker Spaniel, ‘Flush’. So I asked scholar Maureen Adams, who has studied extensively the works and letters of Elizabeth Barrett-Browning, if she knew of any such references to Flush’s behaviour. She provided me with the following excerpts from Elizabeth Barrett-Browning’s letters:
‘Critics who bark the loudest commonly bark at their own shadow in the glass, as my Flush used to do long & loud before he gained experience & learnt the [in Greek] ‘Know Thyself’ in the apparition of the brown dog with glittering dilating eyes#’’1993, August 8, 1845
‘For Flush, though he began by shivering with rage & barking & howling & gnashing his teeth at the brown dog in the glass, has learnt by experience what that image means, . . . & now contemplates it, serene in natural philosophy’ 2271, March 24, 1846
Also, Maureen found that Flush did bite Robert Browning on two occasions.
While these are interesting accounts of Flush’s behaviour, it’s unlikely that they are indicative of rage syndrome. Indeed, Maureen found that Flush was very protective of Elizabeth Barrett-Browning and believes that this may have been why he bit Robert Browning.
This is not to say, though, that Cockers do not suffer from rage syndrome, rather that the breed seems to have received undue attention in relation to it, and that the implication is that other breeds do not suffer from it. Fortunately, not all publicity for the English Cocker Spaniel has been bad, though. Scamper, the golden Cocker in Enid Blyton’s Secret Seven books, had an impeccable temperament, apparently!
From the outset, it is very important to stress that the information provided here is based on the limited amount of information available on the topic, and that in many cases a diagnosis of ‘rage syndrome’ has been based purely on behavioural signs alone.
So, what happens? Owners report that their dogs are normally healthy and good-natured, but that from time-to-time, and without any warning, the animal will become violently aggressive (biting – barking may occur as well), usually towards the owner or other member of the household, although attacks towards another dog or an object have been recorded in the some cases. During the attack the dog’s eyes appear glazed and its pupils are dilated, and some people have reported that the eyes appear red in colour. In addition, some dogs drool, vomit, defecate and/or urinate during an attack. By all accounts, the dog does not seem to know what it is doing and its behaviour is uncontrollable. Attacks towards people seem to be provoked by very simple and seemingly inconsequential interactions, for example, the owner bending down to pat the dog, the owner brushing past the animal, or the owner giving a command in a normal and friendly manner. Sometimes, just before an attack, owners have noted that their dog’s behaviour changes; the dog appears to be in a trance – it stares or growls at nothing in particular. In other cases, attacks occur soon after the dog has just woken up. After an attack, which usually lasts for up to five minutes, the dog appears to be unaware of what has just happened, is tired/exhausted, and usually goes off to sleep for 30 minutes or more. Afterwards, the dog appears normal and friendly again.
This problem has been recorded in dogs as early as six months of age, but most reported cases involve dogs from one to three years of age. Male dogs are most commonly implicated, but it is not possible to say anything about the neuter status of these dogs, as it has not always been reported in the literature.
Interestingly, the dog in question often occupies a high status position in the owner’s home (a lack of inhibition is present in the relationship with the owner leading to agonistic behaviour) and it may also display territorial aggression.
As mentioned earlier, rage syndrome has become synonymous with the English Cocker Spaniel. However, a number of other breeds have demonstrated this condition, or at least signs indicative of it. These include: American Cocker Spaniel, Bernese Mountain Dog, Bull Terrier, Chesapeake Bay Retriever, Dobermann, English Springer Spaniel, German Shepherd, Golden Retriever, Jack Russell Terrier, Lhaso Apso, Pyrenean Mountain Dog, Rottweiler, St. Bernard, West Highland White Terrier and Yorkshire Terrier. It’s important to note here, though, that in most cases only one dog of each breed has actually been reported on in the scientific literature, and usually only behavioural signs have been used as evidence.
There are a few theories as to what might be causing these outbursts of sudden aggression in dogs.
Although owners will claim that they did nothing to provoke the attack on them, behaviour counsellors have noted that these people often have a problem with status-related aggression with their dog; that the dog sees itself as having a higher status in the household than the owner. In these cases, aggression can occur when the owner inadvertently does something that the dog doesn’t like. These attacks will appear unprovoked because they are often simple, seemingly innocuous things, such as the owner going to pat the dog, to step over the dog, or to take something which is near the dog. Indeed, my research with James Serpell on 1,109 English Cocker Spaniels showed that those which showed aggression ‘suddenly and without apparent reason’ also often showed signs of status-related aggression (eg., aggression when disciplined, aggression when reached for or handled).
It is also important to note that different breeds of dog, and indeed different individual dogs, will have different thresholds for aggression. So it’s possible that a breed such as the Cocker Spaniel has a low threshold for aggression, and this may be partly why it has attracted more negative media attention than some other breeds of dog.
This is a type of epilepsy which manifests itself in the form of behavioural change, rather than the classic fits/convulsions we usually associate with epilepsy. Epilepsies can be broken down into two main groups: primary (idiopathic) and secondary. The primary epilepsies are those for which there is no identifiable brain abnormality other than the seizures themselves; the cause is unknown. Secondary epilepsies are those in which seizures are the consequence of an identifiable lesion (e.g. tumour) or other specific cause. Primary epilepsies can be further broken down into generalized seizures (involving both hemispheres of the brain) and focal seizures (abnormal activity in one region of a hemisphere of the brain). Generalized seizures include the ones most of us associate with epilepsy: loss of consciousness, convulsions and foaming at the mouth. Focal seizures can be either simple (consciousness is preserved during the seizure) or complex (consciousness is impaired during the seizure). We are interested in the complex ones, as this type of epilepsy can manifest itself as behavioural change (e.g. aggression) with impaired consciousness, general signs in common with rage syndrome. Other behavioural changes which have been observed in dogs during a complex focal seizure include sudden fearfulness, barking, ‘fly-catching’ (snapping at the air as if trying to catch flies) and tail chasing. In some cases, vomiting and diarrhoea have also been reported during the seizure. In cats, complex focal seizures manifest themselves in the form of confusion, defensiveness, aggression, hissing, moaning, and involuntary licking and chewing movements.
Focal seizures are thought to originate from a variety of places in the brain: the temporal lobes, limbic system, frontal lobes or the occipital lobes. If the location of the origin of the epileptic seizures is known, then a more specific diagnosis of the condition can me made; eg., temporal lobe epilepsy.
When aggressive behaviour is a feature of an epileptic seizure, typical characteristics of seizures must accompany the aggressive act. That is, the seizure should begin suddenly and without provocation, last for a brief period (approximately one to three minutes) and end abruptly, with the violent act occurring in a context of impaired consciousness (dog is disorientated/ unresponsive).
And while most seizures appear to occur spontaneously, they may be precipitated by a variety of factors. For example, sleep deprivation, emotional stress and even heat in unspayed female dogs can precipitate a seizure. The most common type of trigger in people is flickering light, usually from a TV. Certain sounds can also act as a trigger.
However, although aggression during an epileptic seizure is possible, it has not been frequently documented in the medical or veterinary literature. And yet associations between epilepsy and violence prevail in the popular press and among scientists. A major problem is that some scientists and practitioners fail to distinguish between aggressive behaviours that are directly linked to seizure activity and aggressive behaviours that are related to other factors, such as the presence of other underlying brain abnormalities.
These are seizures which appear to be epileptic in nature (e.g. may appear to be a complex focal seizure), but in fact are not due to epilepsy. Instead, other types of brain dysfunction/disturbance are involved. In the medical literature, people demonstrating uncontrollable rage attacks, which are not due to complex focal seizures, are thought to suffer from intermittent explosive disorder (sometimes also referred to as episodic dyscontrol syndrome or rage). This is characterized by repeated acts of violent, aggressive behaviour in otherwise normal people, and the behaviour is out of proportion to the event that triggers or provokes it. Attacks are followed by fatigue, amnesia and sincere remorse. Sufferers are usually male and it is thought that problems in the temporal lobe/limbic system areas of the brain are the cause.
The problem we face initially with diagnosing what is actually causing the sudden aggressive outbursts in dogs is that the behavioural signs are common to all three causes detailed above. Without further investigation, we cannot make a definite diagnosis.
The challenge is being able to diagnose the problem correctly; a full medical, behavioural and neurological examination is required. It is important to remember, too, that aggressive outbursts may be the result of something other than rage syndrome, for example, brain tumours, toxicity (e.g. lead poisoning), infectious/inflammatory diseases, head trauma and metabolic disorders (eg., low blood sugar).
I believe that rage syndrome should only be used to refer to nonepileptic behavioural seizures which manifest themselves in the form of sudden aggression. In people, these types of seizures have been labelled intermittent explosive disorder, episodic dyscontrol syndrome or rage attacks. When we have evidence that the aggressive outbursts are actually epileptic seizures, then the diagnosis should be behavioural epilepsy/complex focal seizure. But just to complicate things a little, human sufferers of nonepileptic behavioural seizures sometimes also have epilepsy! So we need to consider the possibility that a dog showing behavioural seizures may be suffering from both rage syndrome and epilepsy. Where there is no evidence of behavioural seizures (epileptic or nonepileptic) a diagnosis of status-related aggression would be more appropriate – this is not rage syndrome.
So how do we find clinical evidence of behavioural seizures? To date, the best diagnostic tool is an electroencephalogram (EEG). This is a recording of the electrical activity of the brain, abnormalities of which can indicate a variety of brain disorders, including epilepsy. Complex focal seizures always show an abnormal EEG during a seizure. For nonepileptic seizures, the EEG will always be normal during a seizure, while non-specific abnormal activity occurs between seizures.
To date, there have only been a handful of suspected cases which have been fully documented in the scientific literature. In addition, reports from both UK and USA behaviour counsellors suggest that very few cases have been seen in clinics. From my research on English Cocker Spaniels, it was found that approximately 8% of these dogs regularly showed aggression ‘suddenly and without apparent reason’. An earlier Dutch study on 404 Bernese Mountain Dogs found that approximately 20% of them showed ‘intermittent attacks of blind aggressiveness towards their owners’. However, these were both questionnaire-based studies, and full behavioural and medical/neurological assessments on these dogs were not conducted. Consequently, we can’t say anything about the dogs in terms of how many actually suffered from rage syndrome. Indeed, from my research on English Cockers, most of the potential ragers also showed behaviours indicative of status-related aggression.
What we do know is that seizures are the most common neurological problem reported in dogs: approximately 0.5 to 5.7% of dogs have experienced seizures sometime in their lives. This is most likely an underestimate, though, as many people do not know that seizures may manifest themselves in the form of behavioural change and because owners may not bother to take their dog to their veterinarian if the seizures are minor or infrequent. A recent study on Poodles and Dalmatians who had seizures showed that the majority suffered complex focal seizures, although none manifested themselves in the form of sudden aggression. The behavioural manifestations observed were ‘fly catching’ and sudden fear.
There certainly is potential for this because, based on pedigree analyses, a genetic basis for primary (idiopathic) epilepsy in several breeds has been shown. The breeds included are Beagle, Belgian Tervuren, Keeshond, Dachshund, German Shepherd Dog, Labrador Retriever, Golden Retriever and Collie. As to whether complex focal seizures manifesting as aggressive behaviour are heritable, the jury is out, as not enough studies have been conducted.
From my own research on English Cocker Spaniels, it was clear that solid-coloured Cockers (red/golden, black) displayed most types of aggression, including ‘suddenly and without apparent reason’, much more commonly than did parti-coloured Cockers (eg., blue roan, black & white). And because solid and parti-coloured Cockers come from distinct bloodlines, this is a pointer to there being a genetic basis for the difference. However, this is not evidence for rage syndrome being genetic, as it was not possible to determine which, if any, of the dogs in the study actually suffered from it.
If a dog is found to be showing only status-related aggression – and therefore is not rage syndrome – a behaviour counsellor can advise the owner on how to change their behaviour to bring about a more balanced and harmonious dog–owner relationship, with the owner firmly in control. The chances then of aggressive outbursts from the dog should be very greatly reduced or even extinguished.
For dogs suffering from epileptic and nonepileptic behavioural seizures, manifesting themselves as sudden aggression, anticonvulsant medications such as phenobarbitone, primidone and potassium bromide are the drugs of choice. Nonepileptic seizures may also be controlled using other mood-stabilising drugs, such as clomipramine. In addition, if specific triggers (certain sounds, owner behaviour) for these seizures can be identified, then it may be possible to advise the owner on how to avoid them.
At the end of the day, we know very little about rage syndrome. And yet, unfortunately, many people use the term too readily when diagnosing dogs which show unpredictable aggression, especially if that dog happens to be an English Cocker Spaniel. Without conducting full medical, behavioural and neurological assessments, no practitioner can be very certain as to what they are dealing with or how best to treat it.
In the veterinary field, there is a long way to go to understanding and diagnosing neurological problems such as rage syndrome. It’s a fascinating area which deserves much more attention.
I am extremely grateful to Maureen Adams, Laura Marsh, Gail Podberscek and Adrienne Thomas for their help.