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Rage Syndrome, also known as Sudden Onset Aggression, is a serious behavioural problem that has been reported most commonly in the Cocker Spaniel but can also be in a variety of other dog breeds

It is often confused with other forms of aggression and can be misdiagnosed by Veterinarian’s and Behaviourist. This condition is thought to be genetic in origin and can be inheritable. There are a variety of treatments, but each one will need to be tailored to the individual needs of the specific dog.

The rage syndrome in dogs has no connection to Rabie’s as the Latin translation stands for “rage”, although rabies might sometimes be an onset of the syndrome.

A dog with Rage Syndrome will suddenly act aggressively to anyone or anything nearby, but within minutes, it will be calm and normal


The dog often does not seem to remember what has taken place and may act friendly to the person that it previously attacked. Such attacks as these have not stopped and will never be controlled with training. It is a condition that the dog seemingly can not consciously control. The attack will happen without cause or apparent reason and often with no warning signs.

However, if you watch shortly prior to any attack, the eyes will glaze over and go hard. This will be followed by the dog becoming very alert and then finally attacking. Any outsider without knowledge of the condition this will look like an exaggerated form of aggression. There is no trigger or pattern to these attack’s which makes it all the worse to control.

Dr. Roger A. Mugford, to whom the term is attributed, identified that the problem starts on average at around seven and a half months old (adolescent stage). However, some of his research showed signs that it can develop as early as three months and as late as two years. He did find, however, that many dogs displayed their first symptoms on or around one of the five critical learning periods identified in dogs. These occur at six weeks old, 12 weeks old, 24 weeks or six months, one year old, and two years old.

The Cocker Spaniels

Reports show that “Rage” or Rage syndrome was found to be more common in full coloured Cocker Spaniels like the red, golden/blonde or black cockers than in any other colour and a lot had to do with specific breed lines. If the breed line had Rage syndrome, it tended to have a higher occurrence. Solid coloured cockers tend to be at higher risk than their multi-coloured counterparts, with darker colours being most affected.

It is most often associated with the show lines of the breed, although we are starting to see many more cases in the working lines. The colour of the dog may not actually be genetically related; however, it will likely reflect certain bloodline. The Cocker spaniel breeders do not as a rule breed solid colours to part-colours or tri-colours. This is so the two colour phases tend to be distinctive. Previous research in foxes in the 1970s linked particular coat colours with certain extreme behaviours and aggression. However, this is not conclusive evidence that coat colour makes a difference to behaviour in dogs.

English Springer Spaniels

Rage syndrome is sometimes called “Springer rage”, it again is predominantly the show lines that suffer from this disorder. There have been no reported cases in the working lines of the Springer Spaniel breed.

Although scientific evidence is limited, the disorder commonly known as rage syndrome has been described as like an epileptic disorder as it affects the emotion-related parts of the dog’s brain. There is some evidence that in at least some cases, it is an inheritable genetic disorder. In the Springer, Spaniel rage syndrome has been traced back to a winner at the Westminster Kennel Club show who went on to become a top stud dog.

Often it can take too long to successfully diagnose rage syndrome and owners may often not realise the condition’s existence, they may be told by Vets, Trainers and Behaviourist that it is simply a training issue, or they may just confuse it with other forms of aggression. However, it can only be thoroughly diagnosed by a qualified veterinarian using an EEG similar to the ones used on humans to diagnose Epilepsy or genetic testing.

These tests can sometimes be inconclusive, though.

To save these breeds with Rage syndrome, ultimately selective breeding should remove the disorder from affected breeds. However, for already affected dog, then a variety of treatments, including antiepileptic tablets, have been reported to be effective. Unfortunately, not every treatment works, and for many dogs, as much as we try, no treatments work, leaving euthanasia as the only solution. Remember, not all lines are affected by Rage syndrome and not all full colour. Cockers who show aggression suffer from the disorder.

Always consult your vet first and then seek out a Behaviourist with knowledge of all types of aggression, including Rage syndrome.

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