Very Late-Onset Schizophrenia-Like Psychosis: A Case Report and Critical Literature Review.

Late-life psychosis presents a challenge, wherein a wide range of differential diagnoses should be considered. Very late-onset schizophrenia-like psychosis (VLOSLP) is a nosological entity that remains a conundrum. We provide a comprehensive literature review on the neurobiological underpinnings of VLOSLP. We describe a case that typifies the clinical presentation of VLOSLP. Although not pathognomonic, certain features, namely the two-stage progression of psychotic episode, partition delusions, multimodal hallucinations, and absent formal thought disorder or negative symptoms, are quite suggestive of VLOSLP. Several medical causes that might cause late-life psychosis, including neuroinflammatory/immunology diseases, were ruled out. Neuroimaging revealed basal ganglia lacunar infarctions along with chronic white matter small-vessel ischemic disease. The diagnosis of VLOSLP is based on clinical evidence, and the aforementioned clinical features support this diagnostic hypothesis. This case adds to the growing body of evidence pertaining to the relevance of cerebrovascular risk factors in the pathophysiology of VLOSLP, alongside age-specific neurobiological processes. We hypothesized that microvascular brain lesions disrupt the frontal-subcortical circuitry and uncover other core neuropathological processes. Future research should focus on identifying a specific biomarker that would allow clinicians to more accurately diagnose VLOSLP, differentiate it from other overlapping clinical entities such as dementia or post-stroke psychosis, and provide a tailored treatment for the patient.