Olfactory dysfunction, also known as anosmia and hyposmia, is one of the most prevalent (80-90%) symptoms reported by patients with COVID-19. Outside the context of COVID-19, chemosensory dysfunction has been associated with decreased quality of life, anxiety, depression, and cognitive impairment. In the setting of COVID-19, decreased sense of smell has been positively associated with mood disorders such as anxiety and depression. The short-term and long-term neuropsychiatric implications of the olfactory dysfunction related to COVID-19 are still largely unexplored. Investigation of the neuropsychiatric sequelae of olfactory dysfunction related to COVID-19 infection is particularly critical to characterize the pathological effects of COVID-19 on brain function and to develop strategies to improve patient’s quality of life and mental wellbeing. In this Research Topic, Frontiers aims to highlight studies that investigate the neuropsychiatric, psychological, and cognitive consequences of COVID-19-related olfactory dysfunction, present current advances in the field, and anticipate health care needs for the development of therapeutic interventions.

The Coronavirus Disease 2019 (COVID-19) global pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), has led to the identification of a broad range of post-acute Covid neurological symptoms including cognitive impairments, specific executive dysfunctions with sensorimotor deficits (paresthesia, numbness, or weakness of specific body parts), changes in sleep, changes in taste or smell, hallucinations, emotional distress (anxiety, depression), and fatigue/asthenia. Alarmingly, those post-acute sequelae of COVID-19 (PASC) can occur several weeks after infection, arise after severe, mild, or even asymptomatic SARS-CoV2 infection, and are characterized by the persistence, worsening, or new onset of chronic and debilitating neurological symptoms, which have led to the use of NeuroCOVID syndrome terminology. A link between COVID-19-related neurological symptoms and other neurological diseases has not been clearly established, but an increasing number of studies report an increase in mortality post-SARS-CoV-2 infection and an atypical clinical presentation of COVID-19 in patients with dementia. Another intriguing discovery is that survivors that did not suffer from neurodegenerative diseases before the COVID-19 infection seem to be at high risk for subsequent development of neurological disease and in particular Alzheimer’s disease, and to develop early-dementia symptoms. However, the pathophysiology of those associations is not yet delineated, and more research is needed on NeuroCOVID in both the general population and in specific subgroups affected by neurological disorders. As the COVID-19 pandemic could cause a significant rise in the number of dementia patients in the long term, there is an urgent need to understand how PASC is associated with neurodegenerative disorders or with a worsening of neurologic symptoms in neurologically vulnerable populations.

Linking Neuroscience and Behavior in COVID-19 examines the impact of the virus and pandemic on behavior and mental health. Chapters look at those with pre-existing conditions, including dementia and multiple sclerosis, and how the pandemic has burdened them further. There is also discussion on the mental health consequences the pandemic has had and continues to have on the broad populace, including depression and anxiety, as well as neurological effects of the virus itself. Finally, managing care and treatment of conditions - those preceding, caused by, or emerging for the first time during the pandemic are also detailed. - Discusses the impact of the COVID-19 pandemic and the virus itself on behavior and psychology - Examines comorbidities including Parkinson's disease, neuroinflammation, and autism spectrum disorders - Outlines the management and care for coexisting conditions including brain tumors, multiple sclerosis, and ischemic stroke - Features chapters on the severe damage to the nervous system which may be caused by SARS-CoV-2 infection including myelitis - Contains chapters with key facts, dictionary of terms, summary points, applications to other areas pertinent to each chapter, and policies and procedures

Neurocognitive and neuropsychiatric disorders contribute to a substantial amount of global morbidity and, as such, the identification of their causes is paramount to understanding their underlying pathophysiology as well as treatment and prevention strategies. Infectious Diseases in Neurocognitive and Neuropsychiatric Medicine considers the many infectious diseases that have been associated with cognitive and neuropsychiatric function. In Parts I-III, each chapter focuses on a different disease to cover a range of viral, bacterial, and parasitic diseases in neurocognitive and neuropsychiatric medicine. Part IV considers infectious diseases and clinical conditions and syndromes, while Part V examines the relationship between neurocognitive and neuropsychiatric function and the microbiome and Part VI the relationship with childhood development. In addition to molecular and clinical descriptions of the infectious diseases themselves, many chapters also explore the diseases' basic epidemiological features to consider where they may be exerting the greatest impact on cognitive and neuropsychiatric function. Where they exist, the possible mitigating factors and treatments for the neuropsychiatric and cognitive dysfunction that can be associated with these infectious diseases are also explored. In doing so, this volume examines the neurocognitive and neuropsychiatric disorders associated with infectious disease to better understand the role infections play.

A concise, practical guide to the mental health effects of COVID-19 and its treatments Managing Mental Illness After COVID-19 Infection is a resource for people affected by COVID-19 and their loved ones. As the long-term effects, especially the psychiatric effects, evolve and become more common, people are increasingly searching for answers. This book reviews presentations and treatments for mental illnesses post-COVID-19. Readers will learn about the use of medications, supplements, and behavioral interventions to address these conditions. This engaging and practical book includes numerous tables and other illustrations for easy reference. It provides enough medical detail for patients and their caregivers to better understand the symptoms they may experience, as well as the best ways to investigate and treat those symptoms. However, it is not too complex for the general reader, making it perfect as a standalone book for patients and their families. Learn how and why many people struggle with mental illness following COVID-19 infection Discover what your symptoms may indicate and get advice on how to pursue diagnosis and treatment Find a doctor who can understand and manage the mental and behavioral consequences of COVID-19 Get up to speed on the psychiatric and psychosocial effects of COVID-19 infection This is an excellent resource for the public, policymakers, clinicians, counselors, social workers, and behavioral health coaches that could benefit from the latest research on the psychiatric effects of COVID-19.