Validity and reliability of Leonhard's classification of endogenous psychoses: preliminary report on a prospective 25-to 30-year follow-up study

A 25- to 30-year controlled follow-up investigation of endogenous psychoses started in 1997. The research program labeled "Budapest 2000" was initiate d in 1967 as a controlled prospective study. The assessment of 108 patients and 24 normal control persons has so far been completed. With regard to th e "middle groups" in the Leonhardian classification, diagnoses of bipolar m anic-depressive psychosis, cycloid psychosis, periodic catatonia, systemati c paraphrenia, systematic catatonia and hebephrenia proved to be valid in t he long term. Revision of the category affect-laden paraphrenia seems to be called for.