Epilepsy is the most common serious neurological disorder observed today. Characterised by recurrent unprovoked epileptic seizures, epilepsy affects approximately 40,000 people in Ireland and 50 million people worldwide. Epilepsy is usually controlled, but not cured, with medication – although surgery may be considered in difficult cases. Not all epilepsy syndromes are lifelong, for example some are confined to particular stages of childhood.

Convulsive or other seizure-like activity, non-epileptic in origin, can be observed in many other medical conditions. These non-epileptic seizures can be hard to differentiate and may lead to misdiagnosis. Epilepsy covers conditions with different aetiologies, natural histories and prognoses, each requiring different management strategies. A full medical diagnosis requires a definite categorisation of seizure and syndrome types.

The diagnosis of epilepsy requires the presence of recurrent, unprovoked seizures; accordingly, it is usually made based on the medical history. Downstream of the initial diagnosis of epilepsy several tools are available to the clinician to help determine the etiology of the particular case. EEG, brain MRI, SPECT, PET, and magnetoencephalography may be useful to discover the affected brain region, or classify the epileptic syndrome which in turn would determine the appropriate treatment regime.

The cause of an individual's epilepsy can be divided into two categories: symptomatic and idiopathic. Symptomatic epilepsies originate due to some structural or metabolic abnormality in the brain. This may be the result of:

* genetic conditions such as tuberous sclerosis and ring chromosome 20 syndrome
* complications during pregnancy or birth
* stroke
* head injury
* neurosurgical operations
* bacterial or viral encephalitis
* parasitical infection
* alcohol

The term cryptogenic is used to describe epilepsy where the cause is suspected to be symptomatic but the underlying illness or damage has not been identified.

The term idiopathic means "a disorder unto itself", and not "cause unknown". No other condition has been implicated as the cause of the epilepsy. Idiopathic epilepsies are often but not exclusively genetic and generalized - for example Juvenile Absence Epilepsy.

Certain environmental factors can lead to an increased likelihood of seizures in someone with epilepsy or in certain syndromes. For example:

* being asleep
* the transition between sleep and wakefulness
* tiredness
* illness
* constipation
* menstruation
* stress
* alcohol consumption