Ever since the clinical entity of “Folie à Deux” was first introduced (Lasègue and Falret, 1877), a great number of clinical and theoretical studies have appeared in the literature dealing with this relatively rare and interesting mental syndrome. In the English medical literature, up to date, 93 cases of “Folie à Deux” have been reported (Gralnick, 1942), a further 17 cases of “Folie à Trois” (Wolff, 1957; Dewhurst and Eilenberg, 1961), one case of “Folie Imposée à Quatre” (Ropschitz, 1957), one case of “Psychosis of Association” involving a mother and three sons (Page, 1942) and one case of “Folie à Quatre” involving four members of a family (Gralnick, 1943), have also been reported. I personally recorded one example of “Folie à Trois” at the Lebanon Hospital for Mental Diseases in 1947, involving a mother and her two daughters, and another interesting case of “Folie à Deux” in Baghdad (1961) involving a young boy who broke down under the influence of his spiritualist cousin. During the course of the boy's illness the cousin broke down herself into an acute delusional state. Both patients eventually recovered completely.