Usually just one seizure is not a diagnosis of epilepsy. If you have had two seizures, the chance of having another seizure is as high as 80%, so doctors usually do not make a diagnosis of epilepsy until the patient has had at least two seizures. If you have had more than two seizures and the seizure form is more stereotypical (the seizure form is more similar), consider the possibility of epilepsy. The diagnosis of epilepsy can be confirmed if ancillary tests, such as an electroencephalogram, also suggest abnormal brain activity.