Shared psychotic disorder or folie à deux is a rare and relatively unknown syndrome. Large case series are needed to find out and clarify the etiological factors and the phenomenology of shared psychotic disorder by comparing the cases from different society and cultures. In this study, we reviewed all reported cases of shared psychotic disorder that had been published or presented in Turkey since 1962. To reach this aim, we have searched Pubmed/Medline, ScienceDirect, Google Scholar, Ulakbim Turkish Medical Index, Turkish Psychiatric Index databases for published records originating from Turkey. We have also manually searched poster abstract books of congresses held in Turkey between 1962 and 2009. All cases eligible for inclusion into this study have been evaluated one by one and grouped as primary or secondary cases. The features of these cases were investigated for a number of variables including age, sex, educational level, occupation, the presence of shared delusion and hallucinations, diagnosis, management, onset of illness, family history, IQ, social isolation, the nature of the relationship and classification system used for diagnosis. The results have showed that the syndrome is more frequently observed among women, within same family members and between sisters. Social isolation was the most common risk factor in these patients and most patients shared hallucinations with their partners along with their delusions. Several secondary cases required antipsychotic drugs for the treatment of their symptoms. Though these features were inline with literature findings, the present findings from Turkish population were different from previous studies with regards to the presence of olfactory hallucinations, absence of grandiose delusions and the number of affected family members. The results mostly supported the challenges and discussions in western countries. To understand this most pathological form of interpersonal relationships; longitudinal prospective studies evaluating the psychodynamic formulations , biological factors, risk factors as social isolation, prognostic factors are definitely essential.
Shared psychotic disorder, induced delusional disorder, folie à deux, psychosis