National Institute of Mental Health

Delusions are false personal beliefs that are not subject to reason or contradictory evidence and are not explained by a person’s usual cultural concepts. Delusions may take on different themes. For example, patients suffering from paranoid-type symptoms—roughly one-third of people with schizophrenia—often have delusions of persecution, or false and irrational beliefs that they are being cheated, harassed, poisoned, or conspired against. These patients may believe that they, or a member of the family or someone close to them, are the focus of this persecution. In addition, delusions of grandeur, in which a person may believe he or she is a famous or important figure, may occur in schizophrenia. Sometimes the delusions experienced by people with schizophrenia are quite bizarre; for instance, believing that a neighbor is controlling their behavior with magnetic waves; that people on television are directing special messages to them; or that their thoughts are being broadcast aloud to others.