BACKGROUND This study explored the psychopathological state of a sample of 'late paraphrenic' patients and the reliability of their diagnosis according to the most widely used systems of classification of mental disorders.

METHOD The presence and severity of psychiatric symptoms were assessed with the Present State Examination (PSE), the Scale for the Assessment of Positive Symptoms (SAPS), and the High Royds Evaluation of Negativity (HEN) scale. Patient signs and symptoms were classified according to the PSE9-CATEGO4, DSM-III-R, DSM-IV, and ICD-10 diagnostic systems. Agreement among the 11 most widely used criteria for the diagnosis of schizophrenia was assessed for these patients. These included DSM-III-R, DSM-IV, ICD-10, Schneider, Langfeldt, New Haven Schizophrenia Index, Carpenter, Research Diagnostic Criteria (RDC), Feighner, Taylor & Abrams, and PSE9-CATEGO4. The study assessed 47 patients, including in-patients, out-patients, day-patients, and those in the community. Thirty-three elderly controls were recruited from luncheon clubs in Southwark and Lambeth (London, UK).

RESULTS Patients showed a wide range of delusional ideas, most frequently involving persecution (83.0%) and reference (31.9%). Eighty-three per cent of patients reported some sort of hallucination, most frequently auditory (78.7%). Formal thought disorder was very rare, only one patient showing mild signs of circumstantial speech. No patients exhibited catatonic symptoms or inappropriate affect. Shallow, withdrawn, or constricted affect was found in only 8.5% of patients. The various systems of classification indicated that most patients displayed typical schizophrenic symptoms, although up to one-third of them did not meet criteria for the diagnosis of schizophrenia. There was poor agreement among the different diagnostic schedules as to whether to classify patients as schizophrenic (0.02 < k < 0.45).

CONCLUSION Psychotic states arising in late life are accompanied by various psychiatric symptoms that are not entirely typical of early-onset schizophrenia. The current trend to include 'late paraphrenia' into the diagnosis of schizophrenia or delusional disorder has poor empirical and theoretical bases.