Epilepsy is a neurological disorder that causes seizures or periods of unusual behavior due to abnormal brain activity. While a single seizure does not mean someone has epilepsy, it generally requires at least two unprovoked seizures for an epilepsy diagnosis. Symptoms of seizures can vary widely between individuals but may include temporary confusion, staring spells, jerking movements, loss of consciousness, or psychic symptoms like fear or anxiety. Causes of epilepsy include genetic factors, developmental disorders, head trauma, infectious diseases, and in about half of cases the cause is unknown.