Psychosis and schizophrenia-like disorders in the elderly.

Non-organic, non-affective psychoses that have their first onset in late life have been the subject of diagnostic dispute for many years. Do they represent the late manifestation of more typical schizophrenia but with a delayed onset? Are they cases of "symptomatic schizophrenia" in which some organic brain change associated with ageing gives rise to schizophrenic symptoms? A recent International Consensus established that while cases of schizophrenia are sometimes delayed in their onset to 40 to 59 years of age (late-onset schizophrenia), onset after the age of 60 years is generally associated with a different symptom profile and associated risk factors (very late-onset schizophrenia-like psychosis). In this paper we review the data on the very late-onset schizophrenia-like psychosis patient group and suggest research directions for the future.