Delusional Disorder

In delusional disorder, the patient suffers from 1 or more delusions for a duration of 1 month or more, without any other psychotic symptoms or behavioral changes and no decline in functioning abilities. Diagnosis is clinical and the 1st-line treatment is antipsychotic medications provided within the context of a trusting therapeutic relationship. Psychotherapy based on support and education may be helpful.

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Definition and Epidemiology


Delusional disorder is characterized by unshakable false beliefs held by an individual despite being presented with rational, logical arguments and evidence to support the contrary. 

  • Not shared by the people of the same cultural or religious background
  • Cannot be accounted for by the individual’s level of intelligence 
  • The beliefs are typically difficult for others to understand.


  • Lifetime prevalence: 0.05%–0.1%
  • Men and women are affected equally often.
  • Mean age of onset is 40. 
  • Risk factors:
    • Family history of schizophrenia or schizotypal personality disorder
    • Sensory impairment, especially hearing or vision
    • Fatigue
    • Emotional distress


Table: Different types of delusions with examples
Delusions of persecution
  • Most common
  • The individual believes that they are going to be harmed by a living or nonliving thing.
“My office colleagues are ganging up against me since I am better than them. They want to belittle me in front of my boss.”
Delusions of grandeurThe individual believes that they are very famous, rich, or talented.“The US president is my family friend.”
Delusions of guiltThe individual believes that they are a bad person and have done something terribly wrong for which they deserve to be punished.“It is my fault that my dad is ill.”
Delusions of referenceThe individual misrepresents harmless, non-suspicious events or mere coincidences as being strongly applicable to them.“The news on TV is referencing me!”
Somatic delusions
  • The individual is preoccupied with their body and health.
  • They have false perceptions about their body.
“My nose is too big. My teeth are misshapen.”
Delusions of jealousyThe individual believes that their spouse is being unfaithful based on inconspicuous bits of information.“I know my wife is having an affair with my best friend because I noticed that her clothes were wrinkled.”
Religious delusions
  • The individual believes that they are God, a saint, or an angel.
  • They are convinced they have spiritual powers or were born for a divine purpose.
“I am the next messiah!”
Erotomania or delusions of loveThe individual believes that someone is in love with them.“I am positively certain that Angelina Jolie loves me.”
Nihilistic delusionsThe individual believes that their body, or part of it, does not exist or that they are dead.“I am dead. I don’t have any lungs.”
Delusional memoryThe individual clearly remembers events that did not occur.“On the evening of June 9, 2021, I was abducted from my home by aliens.”
Fantastic delusionsThe individual has bizarre delusions that follow no logic or common sense.“I’m slowly changing into a leopard.”


DSM-V diagnostic criteria

  • Presence of 1 or more delusions 
  • Duration of at least 1 month
  • The patient has never been diagnosed with schizophrenia.
  • Note: Hallucinations might present in delusional disorder, but they are not prominent and only relate to the delusion theme.
  • No significant decline in daily functioning
  • Exclusion of other medical disorders (OCD, body dysmorphic disorder (BDD))
  • Exclusion of substance use or medications being the cause

Additional testing

  • Basic labs: complete metabolic panel
  • Urine toxicology for substance-induced psychosis
  • Cranial CT or MRI


General approach

  • It is difficult to initiate treatment, as patients usually lack insight and refuse medical treatment due to their delusion. 
  • Establish a good rapport, or a therapeutic relationship, before challenging the delusion.
  • Identify the psychosocial stressor that often triggers the delusion.
  • Psychotherapy based on support and education may be helpful.


The 1st-line pharmacologic treatment of delusional disorder is with 2nd-generation antipsychotic medications. 

  • Most widely used substance: risperidone
  • Given for a short period of time
  • Discontinue if no benefits are observed after 6 weeks.


Delusional disorder usually has a good prognosis, with 50% fully recovering and 20% showing significant remission.

Differential Diagnosis

  • Schizophrenia: a chronic mental health disorder that is characterized by positive symptoms (delusions, hallucinations, disorganized speech or behavior) and negative symptoms (flat affect, avolition, anhedonia, poor attention, and alogia). The disorder is associated with a decline in functioning lasting over 6 months. The impairment of function due to the severity and duration of symptoms distinguishes schizophrenia from delusional disorder.
  • Brief psychotic disorder: defined as the presence of 1 or more psychotic symptoms lasting more than 1 day and less than 1 month. The disorder usually has a sudden onset and is often stress related. There is a full return to baseline functioning after the episode. Diagnosis is clinical, and treatment includes a brief course of 2nd-generation antipsychotics along with education and reassurance. Unlike delusional disorder, brief psychotic disorder is characterized by impairment of function.


  1. Sadock, BJ, Sadock, VA, & Ruiz, P. (2014). Kaplan and Sadock’s synopsis of psychiatry: Behavioral sciences/clinical psychiatry (11th ed.). Chapter 7, Schizophrenia spectrum and other psychotic disorders, pp. 300–346. Philadelphia, PA: Lippincott Williams and Wilkins.
  2. Manschreck, T. (2020). Delusional disorder. UpToDate. Retrieved March 19, 2021, from
  3. Joseph, SM, & Siddiqui, W. Delusional disorder. [Updated 2020 Nov 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-.

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