In some cultures, epilepsy is a sign of a shaman. Then again, signs of potential shamanic abilities from across the world include manic-depression, bisexuality, insomnia, schizophrenia...
Think about it like this: A medicine man in a tribe has the knowledge of healing plants. If somebody cuts themselves, or has chronic pain, the medicine man (or woman!) should know what to do with what plant. Caring for his tribe this way, he'll also encounter other illnesses, such as depression, anti-social behaviour and even epilepsy. In such a situation, he will have up his sleeve certain plants and techniques to treat the patient.
One of the ways to treat psychiatric/psychic abnormality is to find and encourage the benefits of the condition without struggling futilely forever to cover up the phenomena with drugs. That implies there are benefits to having something like epilepsy. If the girl can be taught a philosophy and practise that can heighten her prophetic abilities, then it will give her the feeling that she's special and gifted rather than sick, and will give her a better quality of life in the long run.
Not that I believe in psychiatry at all - manic depression is called artists temperament in my book
I just thought - the Toronto Blessing experienced by Pentacostals is like an artificially induced epileptic seizure...