Epilepsy is a common neurological condition , often chronic; associated with a sudden and recurrent abnormal brain wave activity in localized areas of the brain. Think of that time you were messing around with the electric wires around your house trying to fix the broken switch. Out of nowhere, you get a quick electric 'shock'! This is exactly  what happens inside the brain 

This disorder cannot be cured, although it is treatable and there are many other different types of treatment options available. Modern medicine has improved much since Ancient Greece. Having seizures can in fact affect your daily life and the lives of those arround you. The cause is still unknown, perhaps this adds on to it being so mysterious.