allucination in schizophrenia. Voices may describe the patient's activities, carry on a conversation, warn of impending dangers, or even issue orders to the individual. Illusions, on the other hand, occur when a sensory stimulus is present but is incorrectly interpreted by the individual.DelusionsDelusions 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.Substance AbuseSubstance abuse is a common concern of the family and friends of people with schizophrenia. Since some people who abuse drugs may show symptoms similar to those of schizophrenia, people with schizophrenia may be mistaken for people "high on drugs." While most researchers do not believe that substance abuse causes schizophrenia, people who have schizophrenia often abuse alcohol and/or drugs, and may have particularly bad reactions to certain drugs. Substance abuse can reduce the effectiveness of treatment for schizophrenia. Stimulants (such as amphetamines or cocaine) may cause major problems for patients with schizophrenia, as may PCP or m...
