Paraphrenia: paranoid states of late life. I. European research.

American psychiatry has traditionally viewed late-life paranoid states either as rare or not part of the schizophrenic syndrome. European psychiatry has not subscribed to this view. The literature (chiefly European) is reviewed from the standpoints of history of the disorder, diagnostic reliability, pre-onset sensory loss, the multiple determinants of paranoia, and the response of paraphrenic patients to treatment with phenothiazines. The evidence leads to the conclusion that late-life paranoid states are not rare, and that the diagnosis "paraphrenia" has real clinical utility. Moreover, there seems to be a substantial relationship between schizophrenia and paraphrenia.