Neuropsychiatric complications of covid-19

Abstract

Viral infections of the respiratory tract can have multisystemic effects, including on the central nervous system (CNS), and thus may precipitate a spectrum of psychiatric and neurological disorders. 1Some patients with covid-19 are now known to develop various CNS abnormalities with potentially serious and long term consequences, including stroke and isolated psychiatric syndromes. 2As covid-19 cases rise again worldwide, it is timely to review what we know and don't know about the acute and chronic neuropsychiatric sequelae and their potential mechanisms.In laboratory studies, SARS-CoV-2 is neurotropic (replicating in neurons) and has the potential to enter the CNS via angiotensin converting enzyme 2 receptors in the olfactory bulb. 3 Whether this happens in clinical populations is unclear.Postmortem studies show evidence of cerebral inflammation, and neuroimaging studies detect leucoencephalopathy and microbleeds in critically ill patients. 4 While viral RNA is typically absent from the cerebrospinal fluid 5 and postmortem brain samples, 6 antibodies to SARS-CoV-2 have been identified in cerebrospinal fluid. 7 Other mechanisms causing CNS dysfunction include cytokine driven inflammatory responses 8 and wider systemic effects such as endotheliopathy, breakdown of the blood-brain barrier, 7 and clotting abnormalities. 6 Additional biological mechanisms, including autoimmunity, may be relevant to psychiatric disorders, as well as the psychological trauma of life threatening illness and pandemic related socioeconomic stressors.The relative contributions of these mechanisms to neuropsychiatric complications remain largely unknown.

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