ABSTRACT
BACKGROUND: Delirium disorder is a frequent neurological complication of SARS-CoV-2 infection and associated with an increased disease severity and mortality. Cognitive impairment is a major risk factor for developing delirium disorder during Covid-19, which, in turn, increases the risk of subsequent neurological complications and cognitive decline. SUMMARY: The bidirectional connection between delirium disorder and dementia likely resides at multiple levels, and its pathophysiological mechanisms during Covid-19 include endothelial damage, blood-brain barrier dysfunction and local inflammation, with activation of microglia and astrocytes. Here, we describe the putative pathogenic pathways underlying delirium disorder during Covid-19 and highlight how they cross with the ones leading to neurodegenerative dementia. KEY MESSAGES: The analysis of the two-sided link can offer useful insights for confronting with long-term neurological consequences of Covid-19 and framing future prevention and early treatment strategies.