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Shared Delusional Disorder

Harold J. Bursztajn, MD and Irene Coletsos, MD Reviewed 04/2024
 


BASICS

DESCRIPTION

  • Shared delusional disorder occurs when a delusional belief held by one person (the “primary”) becomes shared by one other (the “secondary”) or several other people associated with th...

EPIDEMIOLOGY

Incidence

Seen in 1.7 to 2.6% of hospital admissions, per a 2020 German study (1). 

Prevalence

  • “Shared ideas” are more common than “shared psychoses.”

  • WHO estimate the world prevalence of de...

ETIOLOGY AND PATHOPHYSIOLOGY

  • One or more people may come to share in an individual’s delusions or paranoia, most commonly in cases in which those involved are isolated and emotionally close, and the s...

RISK FACTORS

  • A major risk factor for a second person to develop a delusional disorder is to have a close family member (the primary person affected) with a psychiatric diagnosis of schizophrenia, mood...

GENERAL PREVENTION

Adequate treatment for the primary person with mental illness, family therapy for those close to the primary, and bringing such families out of their isolation can help address majo...

COMMONLY ASSOCIATED CONDITIONS

  • Familial mental illness

  • Familial neurologic conditions (dementia)

  • Immigration/displacement from home

  • Massive trauma

  • Hearing (or other sensory) loss, which can lead to misint...

DIAGNOSIS

HISTORY

  • For the primary: may be a history of lack of parental contact leading to feelings of deprivation or excess family strife, in turn leading to emotional overload. A child in such an env...

TREATMENT

  • First, explore whether the primary and secondary patients should be separated: If they are willing to be treated and their relationship is benign, consider treating them together. Also asses...

ONGOING CARE

  • Psychotherapy

  • Care professionals to support the family (or group) involved and try to lessen social isolation

  • Legal involvement if a child/elder/incompetent adult has been victimized

FOLLOW-UP RECOMMENDATIONS

REFERENCES

1
Al Said F, Al Khalil Y. Shared Psychotic Disorder. In StatPearls. Treasure Island, Florida. StatPearls Publishing. January 2021.
2
Pies RW, Pierre JM. “Believing in Conspiracy Theories is N...

CODES

ICD10

  • F24 Shared psychotic disorder

  • F22 Delusional disorders

SNOMED

  • 61831009 Induced psychotic disorder

  • 48500005 delusional disorder (disorder)

CLINICAL PEARLS

  • Rule out medical causes for psychosis.

  • Be aware that delusions occur along a continuum, from a cherished or cultural belief to a pathologically adopted belief system that isolates and m...

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