ICU on the hospital ship USNS Mercy
Lt. j.g. Natasha McClinton, an operating room nurse, prepares a patient for the intensive care unit aboard the hospital ship USNS Comfort in New York Harbor. Navy photo

This pandemic will end, though when exactly remains the prerogative of the novel coronavirus.

And when it’s over, people will begin to reclaim their physical health and well-being. Like our immune systems, we will have taken a body blow, recovered, learned a little about how to better defend ourselves and become stronger for it.

Psychologically, maybe not so much. Our post-pandemic future will likely be fraught with multiple mental health challenges, from rising rates of depression, anxiety, suicidality and delirium to growing evidence that the SARS-CoV-2 virus, which causes the respiratory disease COVID-19, can biologically alter brain function and structure—and thus, one’s mental status.

In a recently published paper, my colleagues Emily Troyer, Jordan N. Kohn and I looked at how past pathogen-driven pandemics affected mental health long after the virus or bacteria had ceased to be a public health threat.

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Reports after influenza pandemics in the 18th and 19th centuries noted increased incidences of various neuropsychiatric symptoms, such as insomnia, mania, psychosis and delirium. Encephalitis lethargica, an inflammatory disorder of the central nervous system marked by hypersomnolence (abnormal sleepiness), psychosis, catatonia and Parkinsonism (movement abnormalities), increased around the time of the 1918 Spanish flu pandemic.

More recently, the pandemics of SARS in 2003 and H1N1 flu in 2009, plus the 2012 MERS outbreak, all generated heightened reports of neuropsychiatric sequelae that included narcolepsy, seizures, encephalitis, encephalopathy, Guillain-Barre syndrome and other neuromuscular and demyelinating processes.

There are already accounts of acute central nervous system associated symptoms in persons affected by COVID-19. In one study, for example, of 217 hospitalized patients in Wuhan, China, neurologic manifestations appeared in almost half of patients with severe infections, including cerebrovascular complications like stroke.

Other reports have described blood chemistry changes associated with these symptoms, such as headache and ataxia (a degenerative disease of the nervous system) and immunological markers linked to persistent neurocognitive deficits. A recent paper by colleagues at UC San Diego School of Medicine validated evidence that loss of smell and taste are common symptoms of COVID-19.

But beyond these immediate harms to our neurological health lie the delayed or chronic neuropsychiatric effects of this pandemic, such as post-infectious autoimmune disorders or the fact that SARS-CoV-2 infiltrates intestinal gut epithelium, and may adversely affect the gut microbiome and the gut-brain axis. We cannot yet say for sure that this happens, but it’s mechanistically possible. We will not fully see or understand these consequences for years.

Past pandemics of this magnitude produced significant evidence of lingering neuropsychiatric harm, but they were also decades or centuries ago and the epidemiological tools required to accurately measure and assess their effects were not strong, or even existent.

Our tools are better today; and our concerns larger. This pandemic will end, but critical work in the global biomedical community is just beginning. We need to launch longitudinal monitoring of neuropsychiatric symptoms and neuroimmune status in persons exposed to SARS-CoV-2, not just in the immediate aftermath but across the course of life, including in utero, throughout childhood development, adulthood and advanced age.

We cannot yet know what we will find, but we can be assured we will see it again—after the next pandemic.

Dr. Suzi Hong is an associate professor in the departments of Family Medicine and Public Health and Psychiatry at the UC San Diego School of Medicine.