As a result of follow-up studies published in 1937 and 1939, Langfeldt divided schizophrenia into two groups; 'typical schizophrenia' which had a poor outcome, and the 'schizophreniform psychoses' which had a less typical clinical picture of schizophrenia and a good outcome. Langfeldt's cases of schizophreniform psychoses were reclassified according to the ICD-9 and DSM-III-R diagnostic systems. Most of the schizophreniform psychoses did not appear 'schizophrenia-like' at all, but turned out to be mainly affective disorders. Those included in Langfeldt's diagnosis of 'schizophreniform psychoses' were found to be too heterogenous to validate the existence of this syndrome.