Genetic or Psychogenic? A Case Study of "Folie à Quatre" Including Twins.

Tohru Ohnuma,Heii Arai

doi:10.1155/2015/983212

Abstract

Shared psychotic disorder, characterized by shared delusion among two or more subjects (termed “Folie à deux,” “trois,” etc.), is often associated with strong religious beliefs or social isolation, factors creating strong psychological sympathy. Recently, we treated a rare familial case of “Folie à quatre” in central Tokyo without such influences. The proband was a schizophrenia patient and younger brother within monozygotic twins. Positive symptoms were “transmitted” to remaining family members, his elder brother, mother, and father father, in a relatively short period of three months. Although the pathophysiology of these positive symptoms (delusions and hallucinations) remains unclear, the transmission pattern suggests the primacy of social and environmental factors (and/or their interaction), while genetics appeared less influential in this “Folie à famille.” Although undiagnosed psychoses in the whole family cannot be excluded, they did not share the other negative schizophrenia symptoms of the proband. A strong familial connection appeared to be the most important factor for the common delusion and hallucination.

Highlights

Shared psychotic disorder is usually “Folie adeux” [1, 2] or more rarely “Folie atrois” [3], while “Folie aquatre” and delusions shared by more than four individuals are extremely rare
We treated a familial case of “Folie aquatre” involving a proband who was a younger brother in a set of monozygotic twins
The proband (A) was diagnosed with schizophrenia according to the Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5) [11]

Summary

Introduction

Shared psychotic disorder is usually “Folie adeux” (delusions shared by two individuals) [1, 2] or more rarely “Folie atrois” [3], while “Folie aquatre” and delusions shared by more than four individuals are extremely rare. We treated a familial case of “Folie aquatre” involving a proband who was a younger brother in a set of monozygotic twins. His delusions and visual hallucinations were transmitted to his older twin brother, mother, and father in a relatively short period of three months after onset. This rare case highlights the importance of shared environmental factors (strong familial bonds) as discussed in a recent review [10]. This case did not involve strong religiosity or a closed environment, which are frequent factors in shared psychotic disorder

Case Presentation

Discussion

Conflict of Interests