Epileptic expatriate international health insurance customers could have this condition due to a number of different causes.
This is according to Epilepsy Research UK's research and information executive Delphine van der Paiw, who said "not all of them have been discovered".
Furthermore, "a lot of investigation" is required in how environmental and genetic factors combine, she continued.
The expert claimed researchers have made discoveries about molecules that can be pharmacologically blocked to prevent seizures.
Currently, around two-thirds of all sufferers of this condition can control their episodes with medication, Ms van der Pauw stated, noting that a "licensed preventative treatment" has not been conclusively found.
"More research is needed" before this occurs, she argued.
A recent investigation published in the medical journal of the American Academy of Neurology found adults that were significantly preterm at birth (23-31 weeks) are five times more likely to be hospitalised due to epilepsy when fully grown than those who were full-term babies.