Case Rep Psychiatry. 2015;2015:983212. doi: 10.1155/2015/983212. Epub 2015 Jun 25.
Case reports in psychiatry
Tohru Ohnuma, Heii Arai
PMID: 26199782 PMCID: PMC4496465 DOI: 10.1155/2015/983212
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.
