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What's Behind Our Brain Fog?
A New York Times analysis blames Long Covid
I’ve been working on a few in-depth articles that I’m excited about, but in the meantime, here are some thoughts on the recent NYT article you may have seen about an increase in cognitive issues reported by younger Americans.
A recent article in The New York Times warns that disability rates are rising in young people and tries to make the case for Long Covid as the driver of this trend. The article was shared by all the usual suspects on Twitter, including Eric Feigl-Ding, Eric Topol, and Lisa Iannattone. Zeynep wrote a long thread on the data, in which she insists that she can’t see “another plausible explanation” and that Long Covid is “the best fit.” But does the data really hold up?
The NYT analysis is based on statistics from a monthly survey done by the US Census Bureau and US Bureau of Labor Statistics called the Current Population Survey (CPS). It’s not a Long Covid survey, but beginning in 2008, the survey has asked these six “disability questions,” and the article focused on the responses to the bolded question, which has increased more than the others in recent years:
Are you deaf, or do you have serious difficulty hearing?
Are you blind, or do you have serious difficulty seeing, even when wearing glasses?
Because of a physical, mental, or emotional condition, do you have serious difficulty concentrating, remembering, or making decisions?
Do you have serious difficulty walking or climbing stairs?
Do you have difficulty dressing or bathing?
Because of a physical, mental, or emotional condition, do you have difficulty doing errands alone such as visiting a doctor’s office or shopping?
The article is based on graphing the percent of affirmative responses to the cognitive disability question over time, compared to some of the other disability questions and split out by age (18-44 versus 45-64), as shown in the above graph. The analysis basically consists of looking at this graph and noticing that there was a sharp increase in people ages 18-44 answering “yes” to this question since the start of the pandemic:
“Because of a physical, mental, or emotional condition, do you have serious difficulty concentrating, remembering, or making decisions?”
It’s important to keep in mind that while the chart looks very dramatic, the y-axis only goes to 4%. We’re talking about an increase of less than 1% of the population. While that small percentage is still a large number of Americans, two studies cited in this NYT article estimate Long Covid cognitive issues occur in 20-30% of those infected. Most people have had Covid at this point, and it’s clear we’re not seeing anywhere remotely close to 20-30% of people reporting serious cognitive issues. Even if the increase in Yes responses to this disability question was entirely due to Long Covid, the prevalence is significantly less than most Long Covid advocates claim.
The article claims Long Covid is a major cause behind this increase, providing the following evidence to support this assertion:
Richard Dietz, an economist at the Federal Reserve Bank of New York, analyzed this data a year ago and attributed the increase primarily to Long Covid. Note that he suffers from a condition similar to Long Covid, known as ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome), so he may be particularly sympathetic to and biased toward Long Covid as the mechanism.
Dr. Ziyad Al-Aly confirmed that “cognitive impairment is a ‘hallmark of long Covid’.” Dr. Al-Aly is an epidemiologist known for a series of Long Covid studies based on electronic health records (EHR) from the Veterans Administration. The studies have been highly criticized by many respected doctors, researchers, and other analysts due to issues with the dataset (VA patients skew to older men and EHR data is messy) as well as other problems with his methodology and interpretation of the data.
Two systematic reviews cited in the article place estimates of cognitive impairment after Covid infections at 20% and 30%. Both of those papers include many weak and biased studies with issues such as: very small sample size, older and/or hospitalized patients, patients referred to Long Covid clinics, subjective cognitive complaints, lack of controls, etc. These estimates simply can’t considered an accurate estimate of prevalence of Long Covid cognitive issues in the population at large.
Some research indicates that biological changes from the virus could affect cognition, such as through brain inflammation or reduced serotonin levels.
Anecdotes about two young people (age 30 and 31) who suffered from Long Covid are included in the article — one has primarily cognitive issues, and the other has more significant issues and is essentially bedridden.
The article does admit that there is another possibility behind the increase in cognitive issues in young people.
“Long Covid is probably not the only factor driving the increase in disability, experts say.”
Looking at the graph, you can see that cognitive issues had already been increasing for young people prior to 2020. Experts have pointed to rising ADHD and autism diagnoses as a reason that young people may be more aware of and willing to report cognitive issues. It’s also become more socially acceptable to embrace mental health diagnoses in recent years.
Additionally, in response to Covid, the whole of society was changed in many significant ways that adversely affected people’s mental health. Depression is known to cause issues with attention, memory, and decision making. Anxiety can interfere with the ability to concentrate and can also cause insomnia, which further contributes to brain fog. And chronic stress can impair memory and concentration directly, as well as lead to other mental health issues. Many of these issues were disproportionately seen in younger adults.
The article includes Dr. Margaret Sibley, a professor of psychiatry, acknowledged that pandemic stress may have worsened ADHD and other mental health issues. In addition, ADHD consultations and medicines also became easier to access via online virtual services during the pandemic, and advertising for ADHD treatment increased, which may have led to an increase in reports of people with difficulties concentrating.
Other Possible Factors
The following factors were not mentioned in the article, but I think are also important considerations with regard to changes we’ve seen over the past few years.
Drugs and alcohol: The pandemic led to an increase in drug and alcohol use, which contributes to cognitive issues like trouble with memory and concentration. In addition, programs like AA often shifted to virtual and many people could not get the support needed to deal with their substance abuse.
Virtual school and work: The sudden switch for much of the population to remote work and school may have contributed to focus and attentiveness issues, as well as fatigue and stress. Not everyone is well-suited to interacting online for much of the day. The Atlantic examined Zoom fatigue in 2022.
Smartphones and social media: An increasing reliance on smartphones and use of social media apps like TikTok built around short-form videos have exacerbated attention issues in many young people. A Wall Street Journal article, TikTok Brain Explained: Why Some Kids Seem Hooked on Social Video Feeds, has been written about this phenomenon.
Social isolation and loneliness: The pandemic disrupted many people’s social interactions and led to intentional and unintentional isolation in many cases. There is a complex relationship between isolation, loneliness, depression, and cognitive decline that can’t be ignored when thinking about cognitive issues during the pandemic.
Grief: Many people lost loved ones during the Covid pandemic, whether due to Covid or some other cause, and it’s well-known that grief can cause a type of brain fog, with impairments to memory and concentration.
Diet and exercise: Many people developed poor dietary habits to deal with pandemic stressors and abandoned healthy habits like regular exercise that may have also contributed to worsening cognitive performance.
Long Covid nocebo effect: The power of suggestion is often overlooked, but there is a sort of negative placebo effect called the nocebo effect that’s a known phenomenon in medicine. Often, the term is used to describe people who report side effects from placebo pills, but a similar phenomenon may be occurring with Long Covid. After hearing about the horrors of Long Covid from public health and in the media, some people may have started to actually perceive those symptoms in themselves after a Covid infection (or even a presumed infection).
It’s likely that a combination of many factors has contributed to the increasing numbers of Americans reporting serious issues with memory, concentration, and decision making. Some of the increase may be the result of true post-viral / auto-immune cognitive impairment. Depression, anxiety, and stress almost certainly play a role as well, along with some of the other possible factors I listed above. I think it’s naïve to assume Long Covid is the lone cause or even major cause of this trend, considering all of the other changes that have occurred in the past four years that have affected people.
Most complex societal problems have multiple causes — I actually found it very odd that Zeynep insisted there would be just one single cause behind the increase. Our society and the way we interact with the world is complex, and slamming on the brakes on society has led to some dramatic results in many aspects of our lives. I think it’s clear that a virus is not the only thing that has caused cognitive issues for Americans over the past four years.
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