Dialogues in Philosophy, Mental and Neuro Sciences

Clinical cases of shared delusion (communicated psychosis) are presented and theoretically discussed for the first time. First, it is clearly stated that usually madness is not contagious, so the reasons explaining cases of interpersonal communication deserve thorough analysis. The authors describe the communication from, respectively, an adult to a child, an adult to an older person, and an older person to an adult.
In all cases there are basic commonalities, i.e. the active person is really delusional but his/her delusion is plausible, otherwise delusional sharing would be harder; the receiving person is of weaker intelligence or (as in the case of children) highly suggestionable; both individuals live in close contact, in the same environment and for a long period. It is noteworthy that even in this paper Laségue shows a particular sensibility for relational issues that are evident in the analysis of cases and in the therapeutic approach.