In the period of planning a prospective study of endogenous psychoses that was later labelled "Budapest 2000", the basic symptom concept of Gerd Huber was adopted in 1967, and a two-part rating scale of subclinical symptoms experienced by the persons themselves (SSRS-Exp) and observed by investigators (SSRS-Behav) was developed in 1974. This research method was employed in assessments of the "Budapest 2000" population at the time of the 5-year follow-up in 1974-1979 and at the time of the 25-30-year follow-up in 1996-2001. With regard to subclinical symptoms, unipolar depressive (DU), manic-depressive (MD) and cycloid psychotic (C) patients do not differ significantly from the normal control persons. Schizophrenic patients are characterised by subclinical symptoms exceeding the level of the normal control persons, but in the group of systematic paraphrenias (SP) and systematic catatonias (SK) this difference is significant only in respect of the SSRS-Behav. Our findings are discussed in terms of nosology. Further analyses of the data gathered by us are needed with regard to construct validity, manifest pathological symptoms, residual states, linguistic expression, and the context of subclinical symptoms.