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
- Emotional distress
|Delusions of persecution||“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 grandeur||The individual believes that they are very famous, rich, or talented.||“The US president is my family friend.”|
|Delusions of guilt||The 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 reference||The individual misrepresents harmless, non-suspicious events or mere coincidences as being strongly applicable to them.||“The news on TV is referencing me!”|
|Somatic delusions||“My nose is too big. My teeth are misshapen.”|
|Delusions of jealousy||The 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||“I am the next messiah!”|
|Erotomania or delusions of love||The individual believes that someone is in love with them.||“I am positively certain that Angelina Jolie loves me.”|
|Nihilistic delusions||The 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 memory||The individual clearly remembers events that did not occur.||“On the evening of June 9, 2021, I was abducted from my home by aliens.”|
|Fantastic delusions||The 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
- Basic labs: complete metabolic panel
- Urine toxicology for substance-induced psychosis
- Cranial CT or MRI
- 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.
- 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.
- 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.
- Manschreck, T. (2020). Delusional disorder. UpToDate. Retrieved March 19, 2021, from https://www.uptodate.com/contents/delusional-disorder
- Joseph, SM, & Siddiqui, W. Delusional disorder. [Updated 2020 Nov 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. https://www.ncbi.nlm.nih.gov/books/NBK539855/