Clinicians who deal with psychotic patients see individuals whose illness is similar to schizophrenia, but whose symptoms are less florid, and deterioration less severe, than in schizophrenia. The diagnosis of atypical psychosis or psychotic disorder NOS is not satisfactory since it lumps disparate conditions together, whereas the term "paraphrenia" can include such illnesses. Paraphrenia is a well-established concept that was ignored in the DSM-III and the DSM-III-R and may be excluded from the ICD-10. There is a need to re-establish the diagnosis, for accurate diagnostic purposes and for future research of the paranoid/delusional disorders.