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COVID Brain: Smelling Is Tough, but Seeing Is Believing

Editor's Note

This story was originally published by MindSite News and is republished with permission.

By Tom Insel, MD, and Matthew Hirschtritt, MD, MPH

Welcome to the Research Roundup. This week, we look at a new study that suggests that the impact of Covid on the brain may extend beyond our sense of smell.

And we examine two studies that examine the effect of race on mental health: One looks at how the impact of racism and trauma is transmitted across generations; the other tracks the declining number of Spanish-language mental health services for a rising number of people needing them. The findings ain’t pretty, but they’re real.

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COVID Brain: Smelling Is Tough, but Seeing Is Believing

You’ve probably heard by now – if you haven’t experienced it yourself – that one of the most common symptoms of Covid infection is a loss of smell. This loss, known as anosmia, is not due to nasal congestion. It could be evidence of the viral infection altering olfactory cells in the nose, but there is also another possibility: It may be altering olfactory pathways in the brain. For all the talk about the brain fog of Covid, the long-term effects of Covid on the brain have not been documented. Until now.

The evidence of Covid’s impact on brain structure is on display in a large, longitudinal study comparing brain scans from infected and uninfected adults ages 51 to 81, using before and after images. Gwenaëlle Douaud and colleagues used the UK BioBank, a massive study of British adults that includes standardized brain imaging protocols. By rescanning participants who had been scanned before contracting Covid, the team was able to see the changes that followed Covid infection. The average duration between scans was 141 days.

Douaud’s team looked at the before and after scans of 401 people who were infected with Covid and compared them to scans from a control group of 384 people who didn’t get Covid. The scans of the infected group showed significant changes in brain structure. The orbitofrontal cortex and parahippocampal gyrus, two areas of the brain important for olfaction (smell) – as well as higher order functions such as judgment, emotional processing, and memory – showed loss of grey matter, suggesting a reduction in neurons or a loss of connections between them.

Other areas of the brain connected to the primary olfactory cortex – the brain’s nerve center for smell – showed signs of tissue damage. As is common in older people, the global brain size of both groups shrank a bit between scans, but the shrinkage was slightly greater in people who had been infected by Covid. The infected also showed more cognitive changes, detected in tests of attention.

Are these changes permanent? Are they progressive? For a pandemic that is slightly more than 2 years old, it is not yet clear whether these changes will persist or whether they increase the risk of dementia or other degenerative changes. But it is already evident that this coronavirus, largely considered a pulmonary infection, has visible consequences on brain structure and function.

This does not mean that the virus directly invades the brain. More likely, these are indirect effects of infection in the nose or of inflammatory processes in the brain. Whatever the mechanism, the loss of smell, brain fog, and other, more subtle effects on mental function are common consequences of Covid infection and may persist as part of the long-Covid syndrome.

SARS-CoV-2 is associated with changes in brain structure in UK Biobank — Nature, March 7, 2022



How Racism – And Mental Health Problems – Get Passed Across Generations

Experiencing racism is a major risk factor for poor mental health and health. These experiences may come in the form of overt discrimination – being stopped unfairly or treated disrespectfully by police – or more subtly through everyday slights and indignities. Experiences like these, especially when they occur repeatedly, can trigger persistent high levels of stress hormones and contribute to mental health and chronic health problems like depression, anxiety, high blood pressure and heart disease. Now a new study shows that these effects extend beyond the person directly experiencing racial discrimination to their adolescent children.

Chardée A. Galán of the University of Southern California and colleagues collected data from 252 Black parent-child pairs who lived in Pittsburgh between 2014 and 2019 at three time points.

In Year 1, at the onset of the study – when youth were between the ages of 9 and 13 years old –parents were surveyed about their experiences with racial microaggressions.

In Year 2, parents were interviewed about their depression symptoms while children took part in computer-based interviews geared to identify behavioral and emotional problems. The kids were also asked about parent-child conflict.

Finally, in Year 3, the young people took part in interviews about their experience with depression, anxiety, and behavioral or conduct problems while parents were asked to rate their children’s behavioral and emotional problems.

The researchers showed that Black parents’ experiences of racism at the beginning of the study predicted higher levels of parent-child conflict a year later and that, in turn, predicted higher levels of youth depression in the third and final year. The models further suggested that the way racial discrimination directed at adults leads to depression in youth – or to anxiety or conduct problems – is through parent-child conflict. This pattern of results held true whether the researchers were assessing the adolescents through interviews with their parents or with the kids.

The study results paint a bleak picture: Black parents experience racism, which leads to conflict with their children, which in turn leads their children to experience mental health issues. This could be Exhibit A in the social determinants of mental health – and points to an urgent need to address structural racism and discrimination.

So how can this be done? One way suggested by the researchers is through racial socialization – conversations between parents and children about racism and racial incidents that help the children understand and process the sting of these experiences and cope with them emotionally and logistically.

Sadly, the results of this study are likely revealing only the tip of the iceberg when it comes to the impact of racism.

Racial Discrimination Experienced by Black Parents: Enduring Mental Health Consequences for Adolescent Youth. — Journal of the American Academy of Child and Adolescent Psychiatry. May 1, 2022.

– Matthew Hirschtritt


Habla Español? At Mental Health Centers, the Answer Increasingly Is No

The need has never been greater for culturally appropriate mental health services for Latinos living in the U.S. – delivered, when needed, in Spanish. And the ability of people to get those linguistically appropriate services? It’s actually declining.

Latinos today make up the largest racial or ethnic “minority” group in the U.S. From 2010 to 2020, the Latino population in the U.S. grew by 23% to over 62 million people. About 28% aren’t fluent in English, and many face other unique stressors including their immigration status, being first-generation residents and exposure to racism and discrimination. Rates of serious mental illness among Latinos have also increased,  growing by 60% from 2015 to 2018 among 18-to-25-year-olds and by 77% among those 26 to 49.

Researchers led by George Pro of the University of Arkansas for Medical Sciences looked at data from the 2014 and 2019 National Mental Health Services Survey, which surveys leaders of private and public mental health facilities. They zeroed in on this single question: “Do staff provide mental health treatment services in Spanish at this facility?”

When they correlated these survey responses with census data, they found that from 2014 to 2019 – a time when the Latino population increased nationally by 4.5% – the proportion of facilities that offered Spanish-language services declined by 17.8% (from 40.5% to 33.3%). That amounts to a loss of over 1,000 mental health facilities with Spanish-language capacity. Only six states – Delaware, Maryland, Montana, Nebraska, New Mexico, and Hawaii – increased the proportion of facilities offering Spanish-language assistance. Every other state had declines.

From 2010 to 2019, the Latino population grew in every state in the country. In general, states with fewer Latinos had the biggest drop in Spanish-language facilities. For example, from 2014 to 2019, states with the lowest proportion of Latino residents had a 51% drop in mental health facilities offering Spanish services. But even in states with higher proportions of Latinos, there was still a 9% drop in facilities able to provide services in Spanish. Several states – notably Oklahoma, North Dakota, Ohio, Kentucky, and Maine, along with a handful of southern and southeastern states – had substantial increases in Latino residents and substantial decreases in Spanish-language facilities.

By 2060, more than a quarter of Americans will identify as Latino. Providing access to Spanish-language mental health services is a vital step to ensuring health equity – yet the U.S. keeps falling further behind.

Downward National Trends in Mental Health Treatment Offered in Spanish: State Differences by Proportion of Hispanic Residents. — Psychiatric Services, May 3, 2022.

– Matthew Hirschtritt


If you or anyone you know is considering suicide, call the National Suicide Prevention Lifeline at 1-800-273-8255. And if you’re a veteran, press 1.

Originally published: August 9, 2022
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