Life under covid has messed with our brains. Luckily, they were designed to bounce back.
By Dana Smith
Orgies are back. Or at least that’s what advertisers want you to believe. One commercial for chewing gum—whose sales tanked during 2020 because who cares what your breath smells like when you’re wearing a mask—depicts the end of the pandemic as a raucous free-for-all with people embracing in the streets and making out in parks.
The reality is a little different. Americans are slowly coming out of the pandemic, but as they reemerge, there’s still a lot of trauma to process. It’s not just our families, our communities, and our jobs that have changed; our brains have changed too. We’re not the same people we were 18 months ago.
During the winter of 2020, more than 40% of Americans reported symptoms of anxiety or depression, double the rate of the previous year. That number dropped to 30% in June 2021 as vaccinations rose and covid-19 cases fell, but that still leaves nearly one in three Americans struggling with their mental health. In addition to diagnosable symptoms, plenty of people reported experiencing pandemic brain fog, including forgetfulness, difficulty concentrating, and general fuzziness.
Now the question is, can our brains change back? And how can we help them do that?
How stress affects the brain
Every experience changes your brain, either helping you to gain new synapses—the connections between brain cells—or causing you to lose them. This is known as neuroplasticity, and it’s how our brains develop through childhood and adolescence. Neuroplasticity is how we continue to learn and create memories in adulthood, too, although our brains become less flexible as we get older. The process is vital for learning, memory, and general healthy brain function.
But many experiences also cause the brain to lose cells and connections that you wanted or needed to keep. For instance, stress—something almost everyone experienced during the pandemic—can not only destroy existing synapses but also inhibit the growth of new ones.
One way stress does this is by triggering the release of hormones called glucocorticoids, most notably cortisol. In small doses, glucocorticoids help the brain and body respond to a stressor (think: fight or flight) by changing heart rate, respiration, inflammation, and more to increase one’s odds of survival. Once the stressor is gone, the hormone levels recede. With chronic stress, however, the stressor never goes away, and the brain remains flooded with the chemicals. In the long term, elevated levels of glucocorticoids can cause changes that may lead to depression, anxiety, forgetfulness, and inattention.
Scientists haven’t been able to directly study these types of physical brain changes during the pandemic, but they can make inferences from the many mental health surveys conducted over the last 18 months and what they know about stress and the brain from years of previous research.
For example, one study showed that people who experienced financial stressors, like a job loss or economic insecurity, during the pandemic were more likely to develop depression. One of the brain areas hardest hit by chronic stress is the hippocampus, which is important for both memory and mood. These financial stressors would have flooded the hippocampus with glucocorticoids for months, damaging cells, destroying synapses, and ultimately shrinking the region. A smaller hippocampus is one of the hallmarks of depression.
Chronic stress can also alter the prefrontal cortex, the brain’s executive control center, and the amygdala, the fear and anxiety hub. Too many glucocorticoids for too long can impair the connections both within the prefrontal cortex and between it and the amygdala. As a result, the prefrontal cortex loses its ability to control the amygdala, leaving the fear and anxiety center to run unchecked. This pattern of brain activity (too much action in the amygdala and not enough communication with the prefrontal cortex) is common in people who have post-traumatic stress disorder (PTSD), another condition that spiked during the pandemic, particularly among frontline health-care workers.
The social isolation brought on by the pandemic was also likely detrimental to the brain’s structure and function. Loneliness has been linked to reduced volume in the hippocampus and amygdala, as well as decreased connectivity in the prefrontal cortex. Perhaps unsurprisingly, people who lived alone during the pandemic experienced higher rates of depression and anxiety.
Finally, damage to these brain areas affects people not only emotionally but cognitively as well. Many psychologists have attributed pandemic brain fog to chronic stress’s impact on the prefrontal cortex, where it can impair concentration and working memory.
Reversal time
So that’s the bad news. The pandemic hit our brains hard. These negative changes ultimately come down to a stress-induced decrease in neuroplasticity—a loss of cells and synapses instead of the growth of new ones. But don’t despair; there’s some good news. For many people, the brain can spontaneously recover its plasticity once the stress goes away. If life begins to return to normal, so might our brains.
“In a lot of cases, the changes that occur with chronic stress actually abate over time,” says James Herman, a professor of psychiatry and behavioral neuroscience at the University of Cincinnati. “At the level of the brain, you can see a reversal of a lot of these negative effects.”
“If you create for yourself a more enriched environment where you have more possible inputs and interactions and stimuli, then [your brain] will respond to that.”
Rebecca Price, associate professor of psychiatry and psychology at the University of Pittsburgh
In other words, as your routine returns to its pre-pandemic state, your brain should too. The stress hormones will recede as vaccinations continue and the anxiety about dying from a new virus (or killing someone else) subsides. And as you venture out into the world again, all the little things that used to make you happy or challenged you in a good way will do so again, helping your brain to repair the lost connections that those behaviors had once built. For example, just as social isolation is bad for the brain, social interaction is especially good for it. People with larger social networks have more volume and connections in the prefrontal cortex, amygdala, and other brain regions.
Even if you don’t feel like socializing again just yet, maybe push yourself a little anyway. Don’t do anything that feels unsafe, but there is an aspect of “fake it till you make it” in treating some mental illness. In clinical speak, it’s called behavioral activation, which emphasizes getting out and doing things even if you don’t want to. At first, you might not experience the same feelings of joy or fun you used to get from going to a bar or a backyard barbecue, but if you stick with it, these activities will often start to feel easier and can help lift feelings of depression.
Rebecca Price, an associate professor of psychiatry and psychology at the University of Pittsburgh, says behavioral activation might work by enriching your environment, which scientists know leads to the growth of new brain cells, at least in animal models. “Your brain is going to react to the environment that you present to it, so if you are in a deprived, not-enriched environment because you’ve been stuck at home alone, that will probably cause some decreases in the pathways that are available,” she says. “If you create for yourself a more enriched environment where you have more possible inputs and interactions and stimuli, then [your brain] will respond to that.” So get off your couch and go check out a museum, a botanical garden, or an outdoor concert. Your brain will thank you.
Exercise can help too. Chronic stress depletes levels of an important chemical called brain-derived neurotrophic factor (BDNF), which helps promote neuroplasticity. Without BDNF, the brain is less able to repair or replace the cells and connections that are lost to chronic stress. Exercise increases levels of BDNF, especially in the hippocampus and prefrontal cortex, which at least partially explains why exercise can boost both cognition and mood.
Not only does BDNF help new synapses grow, but it may help produce new neurons in the hippocampus, too. For decades, scientists thought that neurogenesis in humans stopped after adolescence, but recent research has shown signs of neuron growth well into old age (though the issue is still hotly contested). Regardless of whether it works through neurogenesis or not, exercise has been shown time and again to improve people’s mood, attention, and cognition; some therapists even prescribe it to treat depression and anxiety. Time to get out there and start sweating.
Turn to treatment
There’s a lot of variation in how people’s brains recover from stress and trauma, and not everyone will bounce back from the pandemic so easily.
“Some people just seem to be more vulnerable to getting into a chronic state where they get stuck in something like depression or anxiety,” says Price. In these situations, therapy or medication might be required.
Some scientists now think that psychotherapy for depression and anxiety works at least in part by changing brain activity, and that getting the brain to fire in new patterns is a first step to getting it to wire in new patterns. A review paper that assessed psychotherapy for different anxiety disorders found that the treatment was most effective in people who displayed more activity in the prefrontal cortex after several weeks of therapy than they did beforehand—particularly when the area was exerting control over the brain’s fear center.
Other researchers are trying to change people’s brain activity using video games. Adam Gazzaley, a professor of neurology at the University of California, San Francisco, developed the first brain-training game to receive FDA approval for its ability to treat ADHD in kids. The game has also been shown to improve attention span in adults. What’s more, EEG studies revealed greater functional connectivity involving the prefrontal cortex, suggesting a boost in neuroplasticity in the region.
Now Gazzaley wants to use the game to treat people with pandemic brain fog. “We think in terms of covid recovery there’s an incredible opportunity here,” he says. “I believe that attention as a system can help across the breadth of [mental health] conditions and symptoms that people are suffering, especially due to covid.”
While the effects of brain-training games on mental health and neuroplasticity are still up for debate, there’s abundant evidence for the benefits of psychoactive medications. In 1996, psychiatrist Yvette Sheline, now a professor at the University of Pennsylvania, was the first to show that people with depression had significantly smaller hippocampi than non-depressed people, and that the size of that brain region was related to how long and how severely they had been depressed. Seven years later, she found that if people with depression took antidepressants, they had less volume loss in the region.
That discovery shifted many researchers’ perspectives on how traditional antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs), help people with depression and anxiety. As their name suggests, SSRIs target the neurochemical serotonin, increasing its levels in synapses. Serotonin is involved in several basic bodily functions, including digestion and sleep. It also helps to regulate mood, and scientists long assumed that was how the drugs worked as antidepressants. However, recent research suggests that SSRIs may also have a neuroplastic effect by boosting BDNF, especially in the hippocampus, which could help restore healthy brain function in the area. One of the newest antidepressants approved in the US, ketamine, also appears to increase BDNF levels and promote synapse growth in the brain, providing additional support for the neuroplasticity theory.
The next frontier in pharmaceutical research for mental illness involves experimental psychedelics like MDMA and psilocybin, the active ingredient in hallucinogenic mushrooms. Some researchers think that these drugs also enhance plasticity in the brain and, when paired with psychotherapy, can be a powerful treatment.
Not all the changes to our brains from the past year are negative. Neuroscientist David Eagleman, author of the book Livewired: The Inside Story of the Ever-Changing Brain, says that some of those changes may actually have been beneficial. By forcing us out of our ruts and changing our routines, the pandemic may have caused our brains to stretch and grow in new ways.
“This past 14 months have been full of tons of stress, anxiety, depression—they’ve been really hard on everybody,” Eagleman says. “The tiny silver lining is from the point of view of brain plasticity, because we have challenged our brains to do new things and find new ways of doing things. If we hadn’t experienced 2020, we’d still have an old internal model of the world, and we wouldn’t have pushed our brains to make the changes they’ve already made. From a neuroscience point of view, this is most important thing you can do—constantly challenge it, build new pathways, find new ways of seeing the world.”
How to help your brain help itself
While everyone’s brain is different, try these activities to give your brain the best chance of recovering from the pandemic.
- Get out and socialize. People with larger social networks have more volume and connectivity in the prefrontal cortex, amygdala, and other brain regions.
- Try working out. Exercise increases levels of a protein called BDNF that helps promote neuroplasticity and may even contribute to the growth of new neurons.
- Talk to a therapist. Therapy can help you view yourself from a different perspective, and changing your thought patterns can change your brain patterns.
- Enrich your environment. Get out of your pandemic rut and stimulate your brain with a trip to the museum, a botanical garden, or an outdoor concert.
- Take some drugs—but make sure they’re prescribed! Both classic antidepressant drugs, such as SSRIs, and more experimental ones like ketamine and psychedelics are thought to work in part by boosting neuroplasticity.
- Strengthen your prefrontal cortex by exercising your self-control. If you don’t have access to an (FDA-approved) attention-boosting video game, meditation can have a similar benefit.
