Epilepsy is abnormal electrical activity in the brain; like a thunderstorm, can be mild or severe. Minor epilepsy can cause brief alteration in behaviour or in thinking, often followed by drowsiness. The impact on a person's life comes from the unpredictability of attacks and the social consequences, for example, employment and driving. A major epileptic seizure brings a 1 in 10,000 risk of death. Sometimes people with mild epilepsy start to have major seizures. Anti-epilepsy medication has a 70% chance of abolishing epileptic attacks. It is not uncommon for epilepsy to be an incorrect diagnosis.