The predelusional state (PDS) is defined as the set of psychopathologi
c events preceding the crystallization of delusions, and includes stra
nge cognitions, moods, conations, and motor acts that may be fleeting
and defy description. This review exclusively deals with the historic
aspects of PDS. It is noted that during PDS the patient is expected to
report experiences for which, on account of their novelty, he may not
even have a name. Thus, it is quite likely that according to culture
and personal codes and to the conceptual brief of the interviewer, sim
ilar experiences might be reported as depersonalization, bodily sensat
ions, dysphoria, changes in perception of reality or time, dissolution
of ''ego boundaries,'' etc. It is therefore not surprising that since
the 19th century, PDS has been considered a disorder of cognition, em
otions, volition, and consciousness.