Introduction: Shared paranoia disorder, also known as folie à deux, is a fairly uncommon disturbance characterized by the presence of similar psychotic symptoms in two or more individuals . Most often the symptoms are delusional. The 'primary' case, the individual who first develops psychotic symptoms, can be distinguished from one or more 'secondary' cases, in whom the symptoms are induced. Usually two people are involved, although full family case reports are described. These cases are even more uncommon and more difficult to treat. Case report: We describe a case of folie a famille, this condition being a type of shared paranoia disorder. The case involves a father and his three sons and clinical picture appears afterfourth son 's suicide The dead son is the primary' case, whilst his three brothers and his father are 'secondary' cases. The father was admitted to psychiatric unit for in-patient treatment. Conclusions: Treatment success was modérate in terms of improving the features of folie a famille in thefour individuals involved. The first step for a right treatment is a right diagnosis. Social features and family relationships need to be consider.