Subtypologies of schizophrenia based on cross-sectional criteria, such as the nomenclature of the DSMs, have not been successful in identifying valid diagnostic subgroups among patients with schizophrenia. A subtypology that uses criteria to classify individuals on the basis of longitudinal deficits in self-care may identify a more valid subgroup of schizophrenic patients.
Keefe RSE, Frecska E, Apter S, Davidson M, Hirschowitz J, Davis KL. Clinical characteristics of Kraepelinian schizophrenia: Replication and extension of previous findings. American Journal of Psychiatry, 1996; 153(6): 806-811.