Phenomenology, demography and diagnosis in late paraphrenia.

One hundred and one patients with late paraphrenia were examined using the Present State Examination. The established high prevalence rates of female gender, the unmarried state and sensory impairment were confirmed. All of the symptoms of schizophrenia, with the exception of formal thought disorder, were found in the subjects with approximately the same prevalence as reported in schizophrenics with a symptom onset in younger life. The presence of visual hallucinosis was significantly associated with visual impairment, but the same association was not found between auditory hallucinations and deafness. Mean age at onset of symptoms was high at 74.1 years. Using ICD-10 diagnostic criteria the patients were categorized as schizophrenia (61.4%), delusional disorder (30.7%) and schizoaffective disorder (7.9%). Patients in these diagnostic categories differed in their pre-morbid IQ estimations, current cognitive state measured by the Mini-Mental State Examination and in the number of scored positive psychotic PSE symptoms and their systematization of and preoccupation with delusions and hallucinations. There were no significant differences between the patients in the ICD-10 schizophrenia and delusional disorder groups in terms of age at symptom onset, sex ratio, response to treatment, being unmarried, the presence of insight or sensory impairment. The high degree of clinical similarity between patients with late paraphrenia combined with the inability of ICD-10 to define diagnostic subgroups that correspond to patient clusters derived from clinical symptoms or which are meaningfully different from each other in terms of demographic and prognostic factors provide a strong argument for the retention of late paraphrenia as the most appropriate diagnosis for such patients.