Rage syndrome refers to sudden, unprovoked, unpredictable and uncontrollable violent aggression towards another animal, person or object. This problem has been reported in dogs as young as six months but more commonly between one and three years of age and most commonly seen in male dogs. However there is only a very small amount of suspected cases documented in scientific literature and UK and USA behaviour consultants suggest very few cases have been seen in clinics.
This behaviour is often mostly associated with English Cocker Spaniels with solid coat colour and is sometimes referred to as “Cocker Rage”, it is suggested that approximately eight percent of this breed regularly showed aggression suddenly and without apparent reason. However it is thought that other breeds are also affected and these include Bull Terriers, Golden Retrievers, Lhaso Apso and Yorkshire Terriers. A Dutch questionnaire based study carried out on four hundred and four Bernese Mountain Dogs showed twenty percent had showed intermittent attacks towards their owners.
Little information is known about this form of aggression and in many cases a diagnosis of “rage syndrome” has been based purely on behavioural signs. With owners reporting from time to time their good natured healthy pet without any warning becomes violently aggressive usually towards the owner or a family member but in some cases towards another dog or an object . Attacks towards people seem to be provoked by seemingly inconsequential interactions for instance the owner bending over to stroke the dog or giving a command in a normal friendly manner.
In some instances owners have noticed just before an attack the dogs behaviour changes with the dog appearing to be in a trance, starring and growling at nothing in particular. In other cases the attacks happen soon after the dog has awoken. During the attacks the dogs eyes appear to be glazed with dilated pupils and in some cases it has been reported that the eyes appear red in colour. In addition some dogs during the attack my defecate, urinate drool or vomit. The attacks usually last up to five minutes with the dog appearing not to be aware of what has just happened and is usually left tied but after once again awakening from a sleep following the incident appears normal and friendly again.
To fully diagnose this problem correctly a full medical, behavioural and neurological examination is required. Other illness may also cause aggressive out burst including brain tumours, head trauma and metabolic disorders such as low blood sugar.
There are a few theories as to what may cause these sudden outburst of aggression one of which being status related aggression. Complex Focal seizures can manifest themselves as behavioural change for example aggression with impaired consciousness, general signs in common with rage syndrome, however aggression during an epileptic seizure has not been frequently documented.
A recent study on Dalmatians and Poodles showed that the majority suffered complex focal seizures although none manifested themselves in the form of aggression. Also suggested is other types of brain dysfunction/disturbance which may appear epileptic in nature but thought to be caused by problems in the temporal lobe/limbic system area of the brain..
Based on pedigree analyses a genetic basis for primary (idiopathic) epilepsy is several breeds including the Beagle, Dachshund, Collie and German Shepard has been shown but as to whether complex focal seizures manifesting as aggressive behaviour are heritable, they has not been enough studies conducted.
Very little is known about rage syndrome and to date the best clinical tool in finding evidence of behavioural seizures is an electroencephalogram (EEG) which records electrical activity of the brain, showing abnormalities which can indicate a variety of brain disorders including epilepsy.
Once the condition is diagnosed epileptic and none epileptic behavioural seizures can be treaded with anticonvulsant medications. Mood stabilising drugs may also be used in controlling none epileptic seizures. If specific triggers can be identified it may be possible to avoid them and if the problem is found to be status related a behaviour modification program may be implemented. (Poderscek)
Podberscek, A, The APBC Book of Companion Animal Behaviour