The term epilepsy applies to a group of nervous system disorders characterized by recurrent seizures, which are sometimes called convulsions. A seizure occurs when there are abnormal bursts of electrical activity in the brain. Although head trauma, strokes, brain tumors, brain infections, and withdrawal from drugs (including alcohol) can cause seizures, the recurrent seizures of epilepsy are usually idiopathic (of unknown cause). The April 27, 2011, issue of JAMA includes an article about adherence to treatments for epilepsy. This Patient Page is based on one published in the February 4, 2004, issue of JAMA.