Delusions are fixed beliefs that do not change, even when a person is presented with conflicting evidence. Delusions are considered “bizarre” if they are clearly implausible and peers within the same culture cannot understand them. An example of a bizarre delusion is when an individual believes that his or her organs have been replaced with someone else’s without leaving any wounds or scars. An example of a nonbizarre delusion is the belief that one is under police surveillance, despite a lack of evidence.
Delusional disorder refers to a condition in which an individual displays one or more delusions for one month or longer. Delusional disorder is distinct from schizophrenia and cannot be diagnosed if a person meets the criteria for schizophrenia. If a person has delusional disorder, functioning is generally not impaired and behavior is not obviously odd, with the exception of the delusion. Delusions may seem believable at face value, and patients may appear normal as long as an outsider does not touch upon their delusional themes. Also, these delusions are not due to a medical condition or substance abuse.
There are several different types of delusional disorders, and each type captures a particular theme within a person’s delusions.
Erotomanic: An individual believes that a person, usually of higher social standing, is in love with him or her.
Grandiose: An individual believes that he or she has some great but unrecognized talent or insight, a special identity, knowledge, power, self-worth, or relationship with someone famous or with God.
Jealous: An individual believes that his or her partner has been unfaithful.
Persecutory: An individual believes that he or she is being cheated, spied on, drugged, followed, slandered, or somehow mistreated.
Somatic: An individual believes that he or she is experiencing physical sensations or bodily dysfunctions, such as foul odors or insects crawling on or under the skin, or is suffering from a general medical condition or defect.
Mixed: An individual exhibits delusions that are characterized by more than one of the above types, but no one theme dominates.
Unspecified: An individual’s delusions do not fall into the described categories or cannot be clearly determined.
The most frequent type of delusional disorder is persecutory. Even so, this condition is rare, with an estimated 0.2 percent of people experiencing it at some point in their lifetime. Delusional disorder is equally likely to occur in males and females. Onset can vary from adolescence to late adulthood but tends to appear later in life.
Delusional disorder is classified as a psychotic disorder, a disorder where a person has trouble recognizing reality. A delusion is a false belief that is based on an incorrect interpretation of reality. Delusions, like all psychotic symptoms, can occur as part of many different psychiatric disorders. But the term delusional disorder is used when delusions are the most prominent symptom.
A person with this illness holds a false belief firmly, despite clear evidence or proof to the contrary. Delusions may involve circumstances that could occur in reality even though they are unlikely (for example, the family next door plotting to kill you). Or they may be considered “bizarre” (for example, feeling controlled by an outside force or having thoughts inserted into your head). A religious or cultural belief that is accepted by other members of the person’s community is not a delusion.
The main symptom is a persistent delusion or delusions (a fixed belief) – for example, about a situation, condition or action – that is not happening but may be plausible in real life. Types include:
Erotomanic – Delusion of a special, loving relationship with another person, usually someone famous or of higher standing. (This kind of delusion is sometimes at the root of stalking behavior.)
Grandiose – Delusion that the person has a special power or ability, or a special relationship with a powerful person or figure, such as the president, a celebrity or the Pope.
Jealous – Delusion that a sexual partner is being unfaithful.
Persecutory – Delusion that the person is being threatened or maltreated.
Somatic – Delusion of having a physical illness or defect.
They usually include:
Non-bizarre delusions — these are the most obvious symptom
Irritable, angry, or low mood
Hallucinations (seeing, hearing, or feeling things that aren’t really there) related to the delusion. For example, someone who believes they have an odor problem might smell a bad odor.
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.
Genetic. The fact that delusional disorder is more common in people who have family members with delusional disorder or schizophrenia suggests there might be a genetic factor involved. It is believed that, as with other mental disorders, a tendency to develop delusional disorder might be passed on from parents to their children.
Biological. Researchers are studying how abnormalities of certain areas of the brain might be involved in the development of delusional disorders. An imbalance of certain chemicals in the brain, called neurotransmitters, also has been linked to the formation of delusional symptoms. Neurotransmitters are substances that help nerve cells in the brain send messages to each other. An imbalance in these chemicals can interfere with the transmission of messages, leading to symptoms.
Environmental/psychological. Evidence suggests that delusional disorder can be triggered by stress. Alcohol and drug abuse also might contribute to the condition. People who tend to be isolated, such as immigrants or those with poor sight and hearing, appear to be more vulnerable to developing delusional disorder.
If you have symptoms of delusional disorder, your doctor will likely give you a complete medical history and physical exam. Although there are no lab tests to specifically diagnose delusional disorder, the doctor might use diagnostic tests, such as imaging studies or blood tests, to rule out physical illness as the cause of the symptoms. These include:
Other schizophrenia spectrum disorders
If the doctor finds no physical reason for the symptoms, they might refer the person to a psychiatrist or psychologist, health care professionals trained to diagnose and treat mental illnesses. They’ll use interview and assessment tools to evaluate the person for a psychotic disorder.
The doctor or therapist bases the diagnosis on the person’s symptoms and their own observation of the person’s attitude and behavior. They’ll decide if the symptoms point to a disorder.
Delusional disorder is a challenging condition to treat. People with this condition will rarely admit that their beliefs are delusions or are problematic, and will therefore rarely seek out treatment. If they are in treatment, their provider may find it difficult to develop a therapeutic relationship with them.
Careful assessment and diagnosis are critical to the treatment of delusional disorders. Because delusions are often ambiguous and are present in other conditions, it may be difficult to zero in on a diagnosis of delusional disorder. Additionally, coexisting psychiatric disorders should be identified and treated accordingly.
Treatment of delusional disorder often involves both psychopharmacology and psychotherapy. Given the chronic nature of this condition, treatment strategies should be tailored to the individual needs of the patient and focus on maintaining social function and improving quality of life. Establishing a therapeutic alliance as well as establishing treatment goals that are acceptable to the patient should be prioritized. Avoiding direct confrontation of the delusional symptoms enhances the possibility of treatment compliance and response. Hospitalization should be considered if the potential for self-harm or violence exists.
Antipsychotic medications may be used in the treatment of delusional disorder, although research on the efficacy of this form of treatment has been inconclusive. Studies have shown that somatic delusions appear potentially more responsive to antipsychotic therapy than other types of delusions. Antidepressants, such as SSRI’s and clomipramine, have also been successfully used for the treatment of somatic type delusional disorder.
For most patients with delusional disorder, some form of supportive therapy is helpful. The goals of supportive therapy include facilitating treatment adherence and providing education about the illness and its treatment. Educational and social interventions can include social-skills training (such as not discussing delusional beliefs in social settings) and minimizing risk factors, including sensory impairment, isolation, stress, and precipitants of violence. Providing realistic guidance and assistance in dealing with problems stemming from the delusional disorder may be very helpful.
Cognitive therapeutic approaches may be useful for some patients. In this form of therapy, the therapist uses interactive questioning and behavioral experiments to help the patient to identify problematic beliefs and then to replace them with alternative, more adaptive thinking. Discussion of the unrealistic nature of delusional beliefs should be done gently and only after rapport with the patient has been established.
In addition to encouraging an individual with delusional disorder to seek help, family, friends, and peer groups can provide support and encouragement. It is important that goals be attainable, since a patient who feels pressured or repeatedly criticized by others will likely experience stress, which can lead to a worsening of symptoms. A positive approach may be helpful and perhaps more effective in the long run than criticism.
Outlook for People With Delusional Disorder
It varies, depending on the person, the type of delusional disorder, and the person’s life circumstances, including the presence of support and a willingness to stick with treatment.
Delusional disorder is typically a chronic (ongoing) condition, but when properly treated, many people can find relief from their symptoms. Some recover completely, while others have bouts of delusional beliefs with periods of remission (lack of symptoms).
Unfortunately, many people with this disorder don’t seek help. It’s often hard for people with a mental disorder to know they aren’t well. Or they may credit their symptoms to other things, like the environment. They also might be too embarrassed or afraid to seek treatment. Without treatment, delusional disorder can be a lifelong illness.
There’s no known way to prevent delusional disorder. But early diagnosis and treatment can help lessen the disruption to the person’s life, family, and friendships.