Delusional disorder, previously called paranoid disorder, is a type of serious mental illness — called a “psychosis”— in which a person cannot tell what is real from what is imagined. The main feature of this disorder is the presence of delusions, which are unshakable beliefs in something untrue. People with delusional disorder experience non-bizarre delusions, which involve situations that could occur in real life, such as being followed, poisoned, deceived, conspired against, or loved from a distance. These delusions usually involve the misinterpretation of perceptions or experiences. In reality, however, the situations are either not true at all or highly exaggerated.
People with delusional disorder often can continue to socialize and function quite normally, apart from the subject of their delusion, and generally do not behave in an obviously odd or bizarre manner. This is unlike people with other psychotic disorders, who also might have delusions as a symptom of their disorder. In some cases, however, people with delusional disorder might become so preoccupied with their delusions that their lives are disrupted.
Although delusions might be a symptom of more common disorders, such as schizophrenia, delusional disorder itself is rather rare. Delusional disorder most often occurs in middle to late life.
There are different types of delusional disorder based on the main theme of the delusions experienced. The types of delusional disorder include:
As with many other psychotic disorders, the exact cause of delusional disorder is not yet known. Researchers are, however, looking at the role of various genetic, biological, and environmental or psychological factors.
The presence of non-bizarre delusions is the most obvious symptom of this disorder. Other symptoms that might appear include:
If symptoms are present, your doctor will perform a complete medical history and physical examination. Although there are no laboratory tests to specifically diagnose delusional disorder, the doctor might use various diagnostic tests — such as X-rays or blood tests — to rule out physical illness as the cause of your symptoms.
If the doctor finds no physical reason for the symptoms, he or she might refer the person to a psychiatrist or psychologist, health care professionals who are specially trained to diagnose and treat mental illnesses. Psychiatrists and psychologists use specially designed interview and assessment tools to evaluate a person for a psychotic disorder. The doctor or therapist bases his or her diagnosis on the person’s report of symptoms, and his or her observation of the person’s attitude and behavior.
The doctor or therapist then determines if the person’s symptoms point to a specific disorder as outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which is published by the American Psychiatric Association and is the standard reference book for recognized mental illnesses. According to the DSM-5, a diagnosis of delusional disorder is made if a person has non-bizarre delusions for at least one month and does not have the characteristic symptoms of other psychotic disorders, such as schizophrenia.
Treatment for delusional disorder most often includes medication and psychotherapy (a type of counseling); however, delusional disorder is highly resistant to treatment with medication alone. People with severe symptoms or who are at risk of hurting themselves or others might need to be in the hospital until the condition is stabilized.
Psychotherapy is the primary treatment for delusional disorder. It provides a safe environment for patients to discuss their symptoms while encouraging healthier and more functional attitudes and behaviors.
Psychosocial treatments. Various psychosocial treatments can help with the behavioral and psychological problems associated with delusional disorder. Through therapy, patients also can learn to control their symptoms, identify early warning signs of relapse, and develop a relapse prevention plan. Psychosocial therapies include the following:
Medications: The primary medications used to attempt to treat delusional disorder are called anti-psychotics. Medications include the following:
There is no known way to prevent delusional disorder. However, early diagnosis and treatment can help decrease the disruption to the person’s life, family, and friendships.
The outlook for people with delusional disorder varies depending on the person, the type of delusional disorder, and the person’s life circumstances, including the availability of support and a willingness to stick with treatment.
Delusional disorder is typically a chronic (ongoing) condition, but when properly treated, many people with this disorder can find relief from their symptoms. Some people recover completely and others experience episodes of delusional beliefs with periods of remission (lack of symptoms).
Unfortunately, many people with this disorder do not seek help. It often is difficult for people with a mental disorder to recognize that they are not well. They also might be too embarrassed or afraid to seek treatment. Without treatment, delusional disorder can be a life-long illness.
People with delusional disorder might become depressed, often as the result of difficulties associated with the delusions. Acting on the delusions also can lead to violence or legal problems; for example, a person with an erotomanic delusion may stalk or harass the object of his or her delusion, which could lead to arrest. Further, people with this disorder can eventually become alienated from others, especially if their delusions interfere with or damage their relationships.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition. This document was last reviewed on: 01/22/2018