Psychosis is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality." People experiencing psychosis may report hallucinations or delusional beliefs, and they may exhibit personality changes and disorganized thinking. This may be accompanied by unusual or bizarre behavior, as well as difficulty with social interaction and impairment in carrying out the activities of daily living. Psychiatric complications during the course of surgical treatment are well recognized and may range from acute psychotic episodes to problems of overdependency and addiction, as well as from suicidal depression to disruptive ward behavior. Although the exact cause for postoperative psychosis has not been identified, medical and substance-induced mental disorders are commonly diagnosed postoperatively in surgical patients.