Delusion and Delirium in Neurodegenerative Disorders: An Overlooked Relationship?

Abstract

Delusions are part of the neuropsychiatric symptoms that patients suffering from neurodegenerative conditions frequently develop at some point of the disease course and are associated with an increased risk of cognitive and functional decline. Delirium is a syndrome characterized by acute onset of deficits in attention, awareness, and cognition that fluctuate in severity over a short time period. Delusions and delirium are frequently observed in the context of neurodegeneration, and their presence can easily mislead clinicians toward a misdiagnosis of psychiatric disorder further delaying the proper treatment. Risk factors for developing delusion and delirium in neurodegenerative conditions have been investigated separately while the possible interplay between these two conditions has not been explored so far. With this study, we aim to achieve a more comprehensive picture of the relationship between delusions and delirium in neurodegeneration by analyzing prevalence and subtypes of delusions in different neurodegenerative disorders; providing an overview of clinical tools to assess delusions in neurodegenerative patients and how delusions are covered by delirium assessment tools and discussing the possible common pathophysiology mechanisms between delusion and delirium in neurodegenerative patients. A more extensive characterization of the relationship between delusions and delirium may help to understand whether delusions may constitute a risk factor for delirium and may ameliorate the management of both conditions in patients with neurodegenerative disorders.

PET and SPECT imaging as a solid guide to detect and discriminate atypical phenotypes of neurodegenerative disorders

“…143,144 Among NPS, delusions and delirium are the most associated with worse cognitive and functional outcomes. 145 Neuropsychiatric symptoms and cognitive decline are both signs of similar brain pathologies; thus it is crucial to investigate the underlying pathway linking NPS to neurodegeneration.…”

Understanding psychosis

“…Cytokine-induced neuroinflammation can also result from neurocognitive disorders such as Alzheimer disease, Huntington disease, multiple sclerosis, and traumatic brain injuries 46. Depending on the severity and parts of the brain affected, these disorders may be accompanied by hallucinations and delusions 47. Poststroke psychosis includes hallucinations or delusions48 from a cerebral infarction predominately involving right-sided cortical areas 49…”

“…46 Depending on the severity and parts of the brain affected, these disorders may be accompanied by hallucinations and delusions. 47 Poststroke psychosis includes hallucinations or delusions 48 from a cerebral infarction predominately involving right-sided cortical areas. 49 Deafferentation (freeing of motor nerve cells from sensory connections) induces structural changes in the brain.…”

Whole exome screening of neurodevelopmental regression disorders in a cohort of Egyptian patients

“…They include a heterogeneous group of diseases that result from specific genetic and biochemical defects such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, frontotemporal dementia, and the spinocerebellar ataxias. Also, many inherited metabolic disorders with neural regression especially NCLs [ 7 ]. The clinical approach of these disorders counts on the age of onset and developmental abnormalities in the brain.…”