Functional or psychogenic seizures have proved a diagnostic and therapeutic challenge for centuries. Functional seizures can look and feel similar to epileptic seizures but are instead a common and highly disabling form of functional neurologic disorder, or conversion disorder. Consistent with the biopsychosocial model of mental illness, functional seizures are caused by biological, psychological, and social factors unrelated to epileptic discharges. People with functional seizures do not consciously fake their symptoms. Functional seizures can be differentiated from epileptic seizures through the clinical history, features of the seizures themselves, and electroencephalography findings. Psychotherapy is effective in treating functional seizures.