Langfeldt’s cases of schizophreniform psychoses were reclassified according to the ICD-9 and DSM-III-R diagnostic systems. The main purpose was to reexamine the validity of his concept of ‘schizophreniform psychoses’ to see whether it supported the existence of a ‘third psychosis’, and whether his material could be helpful in identifying good prognostic features in schizophrenia. Most of the schizophreniform psychoses turned out to be affective disorders with psychotic features. The number of other psychotic disorders was too small to facilitate a more thorough ex