Once thought to be an affliction predominantly found in single colour male cockers, cocker rage syndrome (hereafter referred to as CRS) can also affect other breeds. But what exactly is it? Is it even real, or is it mere ‘fiction’? Read on to find out…

Cocker Rage Syndrome

While most of us have probably heard of it, few people fully understand what CRS is. Basically, “rage syndrome” is a term that was originally used to represent a group of behaviours occuring in disproportionate numbers of cocker spaniels.

Having appeared to predominantly manifest itself in single colour cockers and, within this group, mostly in males, rage syndrome was later found to be an affliction that can also be found in other breeds.

The word rage is derived from the Latin word for “rabies”, although I hasten to point out that I do by no means wish to suggest that CRS is in any way caused by or related to rabies.

Leading animal psychologist Dr Rodger Mugford, a behavioural therapy pioneer first used the term CRS when researching aggression in Cockers. He found that most dogs observed by him started showing signs of the syndrome at the age of about seven and a half months. Other research has since suggested that this could be as early or late as three months or two years.

Despite a great deal of research, the causes of this condition remain unclear, although it appears to be an inherited problem. Breeders therefore have a large part to play in this genetic, incurable behaviour.

It’s Not Just Cockers…

Many breeds have been diagnosed with this problem, including:

  • Bernard’s
  • Pyrenean Mountain Dogs
  • Golden Retrievers
  • German Shepherds
  • English Springer Spaniels
  • English Bull Terriers
  • Dobermans
  • Chesapeake Bay Retrievers
  • Bernese Mountain Dogs
  • American & English Cocker Spaniels

So, what exactly is this phenomenon – and is it really a syndrome? Presenting itself in the shape of unprovoked attacks, rage syndrome is a type of aggression that is normally directed against family members.

Looking like a somewhat exaggerated form of dominance or status aggression, the syndrome is usually triggered by people unexpectedly approaching the dog while he is dozing, when the dog will snap to alert and attack, biting and savaging. An attack may continue for a while, then stop as suddenly as it began. The dog then often looks confused and may approach the individual it attacked in its usual greeting mode, looking both submissive and quite sorry for itself.

Before an attack, the eyes often go hard and change colour. Apart from this change to the eyes, there is usually no threat posture or warning before the dog launches itself at a person. It has been theorised by various experts that CRS may be a seizure disorder, as opposed to a temperament disorder (i.e. dominance aggression). Recent success in treating some apparent “rage” cases with an anticonvulsant (Phenobarbital) may give this evidence credence.

Could CRS be Related to Medical Conditions?

There are many arguments about whether rage exists as a syndrome and whether it is a condition that is inherited. Some suggest it may be a type of brain disorder or possibly even a reduction in serotonin levels (which is associated with human violence). Others suggest it could be related to “complex partial seizures”, a form of epilepsy.

I have recently found that aggression is also rising in English Springer Spaniels – and that this kind of unprovoked aggression is mainly found in small (about the size of large Cockers) working Springers. Aggression cases involving Springers have certainly increased in the US.

Behavioural sciences professor Dr Ilana Reisler has probably researched this condition more than anyone else. Dr Reisler believes that the condition follows family lines and is associated with reduced serotonin levels. CRS can be difficult to distinguish from “simple” dominance aggression. It is Dr Reisner’s belief that there is a group of dogs that exhibits extreme uncontrolled aggression way beyond territorial or dominant dogs’ “typical” aggressive responses.

I believe that while this rage probably occurs in many breeds, there is an over-representation of Cockers and Springers among these breeds.

Sudden Onset Aggression (SOA)

Out of the many names the condition has over the years been known by, Sudden Onset Aggression, or SOA, has now been adopted by most experts as a somewhat less sensationalised and more accurate description that “Rage Syndrome”, which was more frequently used during the 1980s/90s.

Occasionally, the terms idiopathic aggression (simply meaning “aggression without known cause or condition”) and mental lapse aggression (which I will cover later within this article) are also used. There are numerous theories as to the causes of SOA (some researchers think partial seizure disorder may be the cause) and the disorder is thought to be inherited and appearing in some breeds at much greater frequency than in others.

I personally believe the condition is inherited – and breeders breeding these animals therefore know their dogs are affected by this disposition. This is the reason why I meet so many Cocker Spaniels with resource guarding issues. Almost 70 per cent of all my resource guarding cases involve Cockers – the majority of which are solid colours (as opposed to roans) and normally, these dogs are show bred, not working stock.

Problems usually start at an age of around 7 months, although I have seen cases of both earlier & later onset. To me, it is quite clear that this is genetic. Breeders are therefore knowingly breeding dogs suffering with this condition – which is believed to have started in the late 1950s/early 1960s from a “Best of Breed” Crufts champion.


The terms “rage Syndrome” or CRS are almost certainly used inappropriately to describe aggression failing to fit reported standards, which makes this problem appear far more widespread and common than it is.

Some dogs appearing to have CRS can get aggressive when faced with certain repeatable situations. Such situations may spark numerous reactions. An owner attempting to move a dog off a bed, chair or sofa; or someone leaning over a dog could, for instance, elicit a threat or attack.

The behaviour has a number or triggers that are repeatable. In this case, it is less likely for the problem to be a seizure disorder or CRS – which would lean towards the suggestion that this condition could be related to status, territory or resource guarding.

Having said this, other tests, which were conducted primarily by Dr Reisner, revealed abnormally low serotonin metabolite amounts in the dogs’ cerebral spinal fluid and urine. This would suggest that their aggression was associated to abnormally low serotonin levels in the brain, which corresponds to findings in violent prison inmates and mental patients.

Medical Treatments

One of the brain’s chemical neurotransmitters with a calming effect, serotonin appears to reduce dominance-related aggression in most mammals. While an animal’s social status is not necessarily changed, higher levels of serotonin do decrease the likelihood of this animal making aggressive displays (which may be used in maintaining social positions).

Based on this, serotonin level-increasing medications were used in the treatment of dogs with dominance aggression. In 50 per cent of treated dominant aggressive dogs, a favourable response with decreasing aggressive behaviour was reported.

So, are medical treatments the answer? Ultimately, drugs cannot solve the problem, but it was suggested that their use can make it both easier and safer for owners to change their pet’s social status within the home by use of behavioural modification techniques.

This indicates that, in some individuals at least, dominance aggression may be caused by abnormal chemical levels in the brain. When treating cases of aggression towards humans, it is nonetheless, important to take numerous factors into consideration.

Mental Lapse Aggression

Another type of aggression, known as mental lapse aggression (MLA), has previously also been described as CRS. First described by Dr Bonnie Beaver (Texas A& M), this aggression type has no known cause and affected dogs’ EEG brain wave patterns resemble those of wild animals. As affected dogs fail to respond to treatment with anticonvulsants, MLA is probably not related to a seizure disorder.

Displayed by dogs with sudden violent aggression and progressively becoming worse, MLA can start presenting at any age, although it usually occurs within young adults. Careful behavioural history fails to show any pattern of predictability, and currently, there is no known treatment for this condition – except euthanasia. Probably very rare, this condition can be extremely difficult to tell apart from severe dominance aggression. Sadly, making this distinction is, in the long run, probably not that critical, because in either case, euthanasia is usually the safest course of action.

I believe that MLA is a case of dogs almost reverting back to their primal state and once again becoming much closer to their ancestors – wolves. In other words, they lose their domesticity and revert to being creatures of the wild.

Fits or Seizures

Seizures or fits can also cause episodes of unprovoked aggression, but here, EEGs generally show seizure spikes, which produce a very different brain wave pattern to that of mental lapse aggression.

When it is suspected that seizures are the cause of aggression, typical medical evaluations for any other types of seizure should be carried out by a veterinarian. Dos suffering with seizure-related aggression frequently respond very well to anticonvulsants.

Their owners must, however, be prepared to not only handle the necessary monitoring, but also having to deal with the potential risks involved in owning/living with a dog who displays aggression during seizures. Apart from this, these dogs are handled the same as any other dog with seizures.

Different Forms of Aggression

There are, depending on how things are broken down, probably around 20 different types of aggression in dogs. Multiple forms of aggression within an individual may interact together to trigger single biting episodes.

The term rage syndrome or CRS has at times been applied to a multitude of aggression types, mainly dominance, seizure-related and mental lapse aggression. When discussing the causes, prognosis and subsequent treatment of dogs with aggression, we need to drop this term from our vocabulary.

Successfully treating an aggressive dog is extremely difficult without understanding all factors involved:

Severity of Aggression – Treating dogs who display aggressive behaviours at lower levels (i.e. lip curls, growls, inhibited snaps) will be far easier than treating dogs who virtually explode into violent attacks. The bite’s ferocity and depth also impact the prognosis: if a dog’s bite is powerful and deep, there is a poor chance of successful treatment.

Predictability of Aggression – When situations most likely to trigger aggression can be predicted by owners (i.e. guarding objects or favourite spots), measures to prevent these situations can be taken.

Age of Dog – The age of a dog when aggressive behaviour occurred for the first time also makes a difference. The prognosis will be the poorer the younger a dog was at the time the initial aggression occurred. Bitches showing signs of aggression against owners early should probably not be spayed, as a reduction in their progesterone levels could exacerbate their behaviour.

I have only ever seen two cases with an apparent presence of “rage syndrome”. Both cases involved working English Springer Spaniel lines. Almost all other cases labelled “rage syndrome” were in fact control complex behaviours (i.e. frustration, resource guarding, dominance, etc.)

Could There be a Link to Resource Guarding?

Resource guarding, or possession aggression, as I sometimes call it, is the is the type of aggression I am most commonly asked to treat in Cockers.

Different from and requiring different treatment to “bowl guarding”, resource guarding is the act of protecting objects aggressively. Such objects may include a wide variety of items, including, for instance:

  • Toys, raw hide chews or pigs’ ears
  • The dog’s space, bed or bones
  • Stroking or found/stolen items

The latter may include anything from socks or underwear to tissues or human food.

I really don’t wish to see people getting attacked for not reading signs properly and following the behavioural advice I provide. These cases really require professional help. It could be that these guarding and aggression issues are manifesting themselves within working Cockers & Springers due to a continuously shrinking gene pool.

Genetic problems are invariably increased by pure breeding, as this somewhat narrows gene pools. With almost no more genetic variation, some pools make it almost impossible for breeders to select bad behavioural traits out anymore.

Duration of Aggression – As any type of aggressive behaviour involves a learned component, it makes perfect sense to say that the longer aggression was allowed to go on, the harder convincing the dog that this behaviour is no longer acceptable (“household/pack rules have changed”) will be. Just like all long-standing habits, owners’ behaviours that can lead to aggression will equally be harder to change.

I see resource guarding and dominant/control complex behaviour in lots of Cockers, and I have also treated numerous Springers who bite deep and hard without warning. Personally, I do not think that this constitutes sufficient evidence to class this as “rage syndrome”. It is my belief that far more work must be done before simply labelling this as a “syndrome”.

Although the jury is still a long way from reaching a verdict on what is actually going on, I lean towards erring on the side of early socialisation (or, to be more precise, the lack thereof) and genetics, potentially involving some chemical imbalances. Then, of course, there are (as stated earlier), strong, untreatable medical problems like “mental lapse aggression”.


Finally, I thought it important to mention the current major changes in how we view dominant behaviour, aggression and social status.

Surely, dominance is a relative term, rather than a description of any given dog’s psyche.

The recommendation made by some experts is to drop the whole dominant/submissive paradigm. I personally do not agree with this, as it countermands the fact that, however we choose to look at it, social status is very much apparent in all dogs.

I do sympathise, to some extent, with those claiming that the word “dominance” is defunct, irrelevant and outdated and that we should therefore no longer use it. Sympathising does, however, not mean I agree with these people’s arguments or logic.

Advances within scientific studies have revealed that we were not given the full picture by our prior knowledge base, which was based on a variety of studies that were incomplete at best and completely incorrect in findings at worst.

The new surge of behavioural modification and positive reinforcement-style dog training is proving to be much kinder and far more effective that previously used methods.

In certain aggression cases (including both inter-dog and inter-human aggression), I have used – to great effect – a device called the “Jingler”. Designed & developed by myself, the Jingler assists in realigning dogs’ behaviour so they accept their owners as their resource controllers. This is vital in cases where dogs are pushy and controlling.

Jinglers are effectively the opposite of clickers. Clickers tell dogs when they have done something right. Jinglers do the opposite: they tell dogs when they have done something wrong. Very simple and extremely effective.

I feel it is important to point out here that by “positive training methods”, I do NOT mean “positive only training methods”! Only praising the good while completely ignoring the bad is invariably the perfect recipe for disaster.

The emergence of clicker training has, to many of today’s behavioural and obedience trainers proved a revelation. Fortunately, the training style that insisted dogs should be subservient and that treat- or reward-based training is simply bribery is now dying out.

Although there are still some organisations and places believing that this latter style is the one right way to train, current training techniques thankfully focus on building owner/dog relationships of mutual respect, trust and control.

The techniques I personally use are not connected to pack mentality. I am, after all, not a dog, my dogs are fully aware of this fact and I can therefore not be the “leader of the pack”.

Let us not allow semantics or political correctness to sneak into dog training or behaviour – let us look realistically at what is in front of us: sometimes a joy, sometimes pushy and occasionally – dare I say it – “dominant”.