A systemic phenomenological model that assumes the movability of the Cartesian cut is proposed and elucidated by means of a single exploratory case study. The model assumes that a continuum from purely psychosomatic disorders to RSPK cases exists. The degree of externalization (locus of control) of the affected person serves as an ordering parameter for the location of the Cartesian cut. It turns out that the dynamics of the disorder develops in four phases, like in the RSPK-model of the MPI. (...) However, in contrast to the decline phase of the RSPK cases (because of the NT-axiom), CER cases lead to petrification of the complaints. (shrink)