[Very late onset psychotic symptoms: psychosis or dementia? A phenomenological approach. A systematic review]

Very-late-onset psychotic symptoms (PS) are a common gateway to both neurodegenerative dementias and primary psychiatric disorders. Despite such similarities of clinical expression, there is no consensual guidelines or specific nosographic frame. The purpose of this systematic review was to establish a phenomenological classification of PS among the main neurodegenerative dementias and late-psychosis. It would allowed 1) the aknowledgement of etiology-specific psychotic phenotypes; 2) where appropriate, it would help the clinician to screen the psychiatric symptoms looking dementias; 3) it would justify the phenomenological research of very-late-onset PS among dementias at a pre-clinical cognitive stage to establish a nosographic frame of these PS based on the prognosis of dementia.

Methods: A literature review was conducted searching for very-late-onset PS (>60 years old) in late-onset psychosis and among Alzheimer dementia type and Lewy bodies dementia, focusing on the phenomenological data.

Results: The very-late-onset schizophrenia-like psychosis appears to be a primary psychiatric diagnosis clinically distinct from the PS emerging among established dementias, but remains a heterogeneous entity due to its age-based syndromic aspect. It has been possible to distinguish preferential phenotypes depending on the etiology of the dementia.

Conclusion: The results confirm the interest of the phenomenological approach to distinguish the etiology of the PS among confirmed dementias. Prospective longitudinal studies must examine the early discriminant characteristics of PS in order to enable a better prognostic prediction of the nosographic frame thereby established.