Epileptic Seizures: The ecstasy and agony of possession.
Oliver Sacks, in his book Hallucinations, devotes a chapter (“The Sacred Disease”) to the various states of consciousness experienced by those who undergo epileptic seizures. He describes the seizure experiences of several patients with epilepsy, including one woman who does not want her seizures to continue but who, nonetheless, describes them as a portal to other forms of consciousness.