U.S. flag

An official website of the United States government

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.

Cover of StatPearls

StatPearls [Internet].

Show details

Delusional Disorder

; .

Author Information and Affiliations

Last Update: March 27, 2023.

Continuing Education Activity

A delusion is a fixed false belief based on an inaccurate interpretation of an external reality despite evidence to the contrary. The diagnosis of a delusional disorder is made when a person has one or more non-bizarre (situations that are not real but also not impossible) delusional thoughts for one month or more that cannot be explained by any other condition. An individual's cultural beliefs merit consideration before coming to the diagnosis. Cultural beliefs also impact the content of delusions. In patients with delusional disorder, delusions(s) do not impact the functionality and the patient's behavior is not overtly bizarre. This activity reviews the evaluation and management of delusional disorder and highlights the role of the interprofessional team in caring for affected patients.


  • Describe the different types of delusions.
  • Summarize the epidemiology of delusional disorder.
  • Describe the evaluation of delusional disorder.
  • Employ interprofessional team strategies for improving care coordination and communication to advance care for patients with delusional disorder and improve outcomes.
Access free multiple choice questions on this topic.


A delusion is a fixed false belief based on an inaccurate interpretation of an external reality despite evidence to the contrary. The belief is not congruent with one’s culture or subculture, and almost everyone else knows it to be false.[1]

The diagnosis of a delusional disorder occurs when a person has one or more non-bizarre (situations that can take place in real life, although not real but are possible) delusional thought for one month or more, that has no explanation by another physiological, substance-induced, medical condition or any other mental health condition. An individual's cultural beliefs merit consideration before coming to the diagnosis. Cultural beliefs also impact the content of delusions. 

Other than the delusions(s) the functionality is not impacted, and behavior is not obviously bizarre.

Some of the most frequently encountered types of delusions are:

  1. Delusional jealousy - That one’s sexual partner is unfaithful.
  2. Bizarre - A delusion involving a phenomenon that is impossible, not understandable, and unrelated to normal life.
  3. Erotomanic - A delusion that another person, more frequently someone of higher status is in love with the individual.
  4. Grandiose - A conviction of great talent, discovery, inflated self-worth, power, knowledge, or relationship with someone famous or deity.
  5. Persecutory - The central theme is being conspired against, attacked, harassed, obstructed in the pursuit of long-term goals.
  6. Somatic - These involve bodily functions and sensations.
  7. Mixed - No single theme is prevalent.
  8. Thought broadcasting - Delusion that one's thought is projected and perceived by others.
  9. Thought insertion - A delusion that one's thought is not one's own but inserted into their mind by an external source or entity.


Delusional disorder is relatively rare, has a later age of onset as compared to schizophrenia, and does not show a gender predominance. The patients are also relatively stable. The exact cause of the delusional disorder is unknown.[2]

Many biological conditions like substance use, medical conditions, neurological conditions can cause delusions. The delusional disorder involves the limbic system and basal ganglia in those with intact cortical functioning.[3]

Hypersensitive persons and ego defense mechanisms like reaction formation, projection, and denial are some psychodynamic theories for delusional disorder. Social isolation, envy, distrust, suspicion, and low self-esteem are some of the factors which when becoming intolerable leads to a person seeking an explanation and thus forming a delusion as a solution.[2]

Immigrants with language barriers, deaf and visually impaired persons, as well as the elderly, are special populations who are more vulnerable to delusions.


The lifetime morbid risk of delusional disorder in the general population has been estimated to range from 0.05 to 0.1%, based on data from various sources including case registries, case series, and population-based samples. According to the DSM-V, the lifetime prevalence of delusional disorder is about 0.02%.[3] The prevalence of the delusional disorder is much rarer than other conditions like schizophrenia, bipolar disorder, and other mood disorders; this may be in part due to underreporting of delusional disorder as those with delusional disorder may not seek mental health attention unless forced by family or friends. Age mean age of onset is about 40 years, but the range is from 18 years to 90 years. The persecutory and jealous type of delusion is more common in males, while the erotomanic variety is more common in females.


Generally, global functioning is more or less preserved as compared to other disorders. Impairment can be significant in one's occupation. There may be social isolation. A unique finding is apparent normal psychological functioning and appearance when not discussing the specific delusion. 

  • Persecutory type: This is one of the most common types of delusions and patients can be anxious, irritable, aggressive, or even assaultive - some patients may be litigious.
  • Jealous type: Also known as “ Othello syndrome” this type is more common in males; it can sometimes correlate with suicidal or homicidal ideations, and hence safety is an important consideration in evaluation and management.[4]
  • Erotomanic type: Also known as “ psychose passionelle” this type of delusion involves a belief that a person usually of higher stature is in love with the patient.[5] These patients are usually socially withdrawn, dependent, sexually inhibited with a poor level of social and/or occupational functioning. “Paradoxical conduct” is an important characteristic wherein all denials of affection are rationalized as affirmations.[6] Males with this type of delusion can be more aggressive.[7]
  • Somatic type: Also called monosymptomatic hypochondriacal psychosis and the reality impairment is severe. The patient is unarguably convinced of the severity of the symptoms. The most common type of somatic delusions is that of infestation example with parasites, body dysmorphic delusion, and of body odor or halitosis. These patients also have anxiety and nervousness.
  • Grandiose type: Also known as megalomania are notable for increased self-importance.
  • Mixed type: Patients have two or more delusional themes.
  • Unspecified type: Sometimes a predominant delusion cannot be identified. Capgras syndrome is a delusional syndrome where there is a belief that a known person has been replaced by an impostor.[1] Cotard syndrome is when a patient believes he has lost his possessions, status, and even bodily organs.[1]

Delusional disorder in the partner of an individual with the delusional disorder: This is also known as a shared psychotic disorder.

History and Physical

General description: Patients are usually well-nourished, appropriately groomed. It may seem odd, suspicious, can be litigious. Patients seek an ally in the clinician, but it is important not to accept the delusion as it eventually results in confusing the patient’s reality and leads to distrust.[3]

Mood: Mood is usually congruent with the delusion, for example, a grandiose patient may be euphoric, or a paranoid patient may be anxious. Mild depressive symptoms are present.[8]

Perceptions: Usually no abnormal perceptions are present. Auditory hallucinations may be present in some.

Thought: This is the primary abnormality in delusional disorder. The delusions are not bizarre and are clear as well as systematic for example a cheating spouse, persecutory delusions. It is essential to check the patient's belief before concluding it to be a delusion. Some patients are verbose and circumstantial when describing their delusions. Bizarre delusions more likely correlate with schizophrenia.[3]

Cognition: Memory and cognition are usually intact, and patients are oriented unless there is a specific delusion about person, place, or time.

Impulse control: It is important to evaluate for suicidal or homicidal ideations and plans. If there is a history of aggression with adverse action, then hospitalization should be considered.

Insight and judgment: Most commonly patients have no insight regarding their delusion. Judgment is assessable by a history of past behavior and future plan.


Although there is no set of labs required for a delusional disorder like most other psychiatric disorders. Imaging or laboratory tests should be considered to rule out any organic causes. Substance-induced conditions should be ruled out by getting a urine drug screen. After an organic cause is ruled out a clinical exam should be completed. A clinician would do an assessment and ask further questions about their delusions. During the assessment, a complete mental status exam should be done. Interviewing family members and friends should be considered because they can provide further details about the delusions and more importantly a timeline of the presenting symptoms.

Treatment / Management

The treatment of delusional disorder is difficult considering the lack of insight. A good doctor-patient relationship is a key to treatment success. Treatment includes psychotherapy by establishing trust and building a therapeutic alliance. 

A patient's history of medication compliance is the best guide to select appropriate antipsychotic medication. An antipsychotic should be started for a trial period of six weeks after which there is an evaluation of the effectiveness of the medication. Start a low dose and titrate up as needed. Another drug from another class can be tried after six weeks if no benefit is noted from initial treatment.[9]

Though not a primary indication drugs like lithium, valproic acid, and carbamazepine can be considered as an adjunct treatment if monotherapy with antipsychotics fails.

Treatment response is better when combining psychotherapy with psychopharmacology.

Differential Diagnosis

  1. Obsessive-compulsive disorder: A person who remains convinced that his/her obsessions and compulsions are true convictions, should be given the diagnosis of obsessive-compulsive disorder with absent insight.
  2. Schizophreniform and schizophrenia: This can be differentiated from delusional disorder by the presence of other symptoms of the active phase of schizophrenia.[10]
  3. Delirium/major neurocognitive disorder: Can mimic delusional disorder but distinguished based on the chronology of symptoms.
  4. Depression or bipolar disorder: Delusions occur with mood episodes. A delusional disorder is diagnosed only when the span of delusions exceeds the total duration of mood symptoms.


The prognosis of delusional disorder is better with treatment and medication compliance. Almost 50% of patients have a good response to medications; more than 20% of patients report a decrease in symptoms and less than 20% of patients report minimal to no change in symptoms. Delusional disorder is usually a chronic condition, but when properly treated. A good prognosis is also related to higher social and occupational functioning, early-onset before age 30 years, female, sudden onset of symptoms, and short duration.[2]


The delusional disorder, if left untreated, might lead to depression, often as a consequence of difficulties associated with the delusions. Delusions also can lead to violence or legal issues; for instance, stalking or harassing the object of delusion, could lead to arrest. Further, patients suffering from this disorder can become alienated from others, particularly if their delusions interfere with their social ties.

Deterrence and Patient Education

Patients with a delusional disorder may first have their first encounter with a nurse practitioner or primary care physician. It is important to refer these patients to a mental health counselor or a psychiatrist because the management is complex. Many of these patients lack insight into their disorder and consequently refuse treatment. Therefore, education of the community and family counseling of those who are related to the patient are crucial steps in a holistic approach toward managing a patient suffering from delusional disorder.

Enhancing Healthcare Team Outcomes

Despite treatment, relapses are frequent. The biggest obstacle to treatment is treatment compliance. A mental health nurse should work with the team and follow up on these patients because many eventually run into legal and work-related problems and assist with coordination and follow-up of care. An interprofessional team approach will ultimately result in the best patient outcomes. [Level 5]

Review Questions


Currell EA, Werbeloff N, Hayes JF, Bell V. Cognitive neuropsychiatric analysis of an additional large Capgras delusion case series. Cogn Neuropsychiatry. 2019 Mar;24(2):123-134. [PMC free article: PMC6425915] [PubMed: 30794090]
Mendez I, Axelson D, Castro-Fornieles J, Hafeman D, Goldstein TR, Goldstein BI, Diler R, Borras R, Merranko J, Monk K, Hickey MB, Birmaher B. Psychotic-Like Experiences in Offspring of Parents With Bipolar Disorder and Community Controls: A Longitudinal Study. J Am Acad Child Adolesc Psychiatry. 2019 May;58(5):534-543.e6. [PMC free article: PMC6487225] [PubMed: 30768403]
Kalayasiri R, Kraijak K, Mutirangura A, Maes M. Paranoid schizophrenia and methamphetamine-induced paranoia are both characterized by a similar LINE-1 partial methylation profile, which is more pronounced in paranoid schizophrenia. Schizophr Res. 2019 Jun;208:221-227. [PubMed: 30826260]
Kataoka H, Sugie K. Delusional Jealousy (Othello Syndrome) in 67 Patients with Parkinson's Disease. Front Neurol. 2018;9:129. [PMC free article: PMC5845894] [PubMed: 29563893]
Kelly BD. Love as delusion, delusions of love: erotomania, narcissism and shame. Med Humanit. 2018 Mar;44(1):15-19. [PubMed: 28689196]
Faden J, Levin J, Mistry R, Wang J. Delusional Disorder, Erotomanic Type, Exacerbated by Social Media Use. Case Rep Psychiatry. 2017;2017:8652524. [PMC free article: PMC5359441] [PubMed: 28367347]
Leffa DT, Panzenhagen AC, Salvi AA, Bau CHD, Pires GN, Torres ILS, Rohde LA, Rovaris DL, Grevet EH. Systematic review and meta-analysis of the behavioral effects of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder. Neurosci Biobehav Rev. 2019 May;100:166-179. [PubMed: 30826386]
Cella M, He Z, Killikelly C, Okruszek Ł, Lewis S, Wykes T. Blending active and passive digital technology methods to improve symptom monitoring in early psychosis. Early Interv Psychiatry. 2019 Oct;13(5):1271-1275. [PubMed: 30821079]
Humpston CS, Adams RA, Benrimoh D, Broome MR, Corlett PR, Gerrans P, Horga G, Parr T, Pienkos E, Powers AR, Raballo A, Rosen C, Linden DEJ. From Computation to the First-Person: Auditory-Verbal Hallucinations and Delusions of Thought Interference in Schizophrenia-Spectrum Psychoses. Schizophr Bull. 2019 Feb 01;45(45 Suppl 1):S56-S66. [PMC free article: PMC6357975] [PubMed: 30715542]
Sacchetti E, Valsecchi P, Tamussi E, Paulli L, Morigi R, Vita A. Psychomotor agitation in subjects hospitalized for an acute exacerbation of Schizophrenia. Psychiatry Res. 2018 Dec;270:357-364. [PubMed: 30293014]

Disclosure: Shawn Joseph declares no relevant financial relationships with ineligible companies.

Disclosure: Waquar Siddiqui declares no relevant financial relationships with ineligible companies.

Copyright © 2024, StatPearls Publishing LLC.

This book is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ), which permits others to distribute the work, provided that the article is not altered or used commercially. You are not required to obtain permission to distribute this article, provided that you credit the author and journal.

Bookshelf ID: NBK539855PMID: 30969677


  • PubReader
  • Print View
  • Cite this Page

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Similar articles in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...