This is an email from Inside Your Head 🧠, a newsletter by Elemental.

What Happens in the Brain When You’re Alone

Your brain responds to stress differently when you’re by yourself

Credit: Justin Paget / Getty Images

This is a modified excerpt from Inside Your Head 🧠, a weekly newsletter exploring why your brain makes you think, feel, and act the way you do, written by me, Elemental’s senior writer and a former brain scientist. Subscribe here so you won’t miss the next one.

This week’s issue is a preview from a series of stories I’m working on called “Your Poor Pandemic Brain” to mark the one-year anniversary of the U.S. going into lockdown and what it’s done to our mental health. I’ve been immersed in this topic for the past month, so I thought I’d offer a sneak peek of what I’m finding out.

The past 12 months have been filled with stress — enormous, unending stress that our brains are not evolutionarily equipped to handle. One stressor in particular that is unique to this pandemic and that may have an outsized impact on psychological health is social isolation. This is because loneliness and isolation strip people of one of the most important coping mechanisms that can protect against mental illness: human connection.

I know I’m feeling this. I go days without leaving the house, weeks seeing only my fiancé and my dog. There are Zoom calls with friends and co-workers, but they are a stopgap, and when I sign off, I still feel unconnected, unsatiated. As two of the psychologists interviewed for this piece put it, Zoom calls are the junk food of social interaction; they are the equivalent of a bag of Doritos when you’re starving. You’ll raise your glass on Zoom and shake the bag of crumbs into your mouth, but you’re still left feeling empty.

Your brain, stressed and lonely

“Humans are a social species,” says Julianne Holt-Lunstad, PhD, a professor of psychology and neuroscience at Brigham Young University. “Our brains have evolved to expect proximity to others. Throughout human history, we’ve had to rely on others for survival, and when we lack proximity to others, particularly trusted others, in essence, our brains have to work harder.”

By robbing us of human connection, the coronavirus has also robbed us of our primary means of accessing support and mitigating the ramifications of the many challenges we’re going through right now. This is true on a larger systems level as well as on a cellular one.

Without close proximity to others, the body’s stress response is higher than it might be otherwise. Loneliness and social isolation are also stressful in and of themselves, and they are experienced in the brain as being in a state of general threat, triggering the release of stress hormones.

“All else being equal, when we’re alone, our brain is a little more vigilant for any signs of danger. Also, our brain perceives demands from the world as more demanding than they would be if we had someone with us,” says James Coan, PhD, a professor of psychology at the University of Virginia. “And there’s a really simple reason for it; it’s that the world is more demanding when we’re alone because anything that the world demands of us when we’re alone, we have to do by ourselves.”

Coan has tested this theory through a set of experiments where he scans the brains of people while they’re undergoing a stressful experience — receiving a mild electric shock — both while they’re alone and when they’re holding the hand of a friend or family member. His lab found that parts of the brain’s alert system don’t become as active when the person is shocked in the presence of social support.

“When you’re holding someone’s hand who you trust and know and love, your brain seems to see the threat cue differently than it does when you’re by yourself,” he says. “And what it sees is a cue that’s just less threatening. So you see less blood flow in the brain going to places that process threats and that are also responsible for regulating your behavior in the context of that threat.”

Your brain is hungry for social contact

Another area that changes its activity when you’re alone is the brain’s reward hub. Being around friends and family, or even seeing pictures of loved ones, activates dopamine neurons in the area, just like other rewarding activities like eating, listening to music, or using drugs.

Recently, scientists at MIT discovered that being alone for 10 hours caused activity in the brain similar to going without food for 10 hours. Namely, people craved social contact just like they craved food when they were hungry, and dopamine neurons in the reward circuit lit up more when people saw pictures of food or friends after they had been deprived of those things.

“It highlights how important it is for people to be connected with others,” Livia Tomova, PhD, a postdoc at MIT who conducted the research, said on the Psychology in Action podcast. “If already one day of being alone makes our brains respond as if we had not eaten for a whole day, it suggests that social interactions are a very basic need that we have.”

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental

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