Mentzos characterizes hysteria as a specific transformation of self-representation through a regressive desymbolization. In his view the common criterion of hysterical phenomena is the portrayal, in body language, of an infringement of a somatic or psychic function. The variation of symptoms in hysteria demonstrates how symbolic expression depends on sociological variables. Oedipal flights regularly coincide in time with their hysterical elaboration because the latter depends on certain ego functions which do not mature before the third or fourth year of life. For this reason oedipal conflicts and hysteria have often been mistakenly equated.