The social and treatment consequences of a shared delusional disorder in a homeless family.

Objective: Delusional disorder is defined as a fixed, false belief that is held by a person despite evidence to the contrary. Shared psychotic disorder, also known as folie a' deux, psychosis by association and induced psychotic disorder, is an uncommon and unique psychiatric disorder. It is even more unusual when it occurs within families (folie a' famille). Case Presentation: This case report describes the occurrence of a shared delusion within a family consisting of an adults on and two elderly parents. The shared delusion, which was the belief that a large financial settlement was a waiting to be disbursed to the family members by the local law enforcement agency, contributed to their state of homelessness and rejection of all offers of assistance from service providers. Conclusion: The impact of this shared psychotic disorder contributed to the family's state of extreme poverty and homelessness, which, as a consequence, greatly impeded the initiation of evidence-based therapeutic interventions.