The ADHD Brain

The Science of Loneliness

In the midst of what the U.S. Surgeon General is calling a “loneliness epidemic,” neuroscientists explain what research reveals about the lonely brain.

A image of person with caged emotions of loneliness in mind. Loneliness is defined as the emotional discomfort one feels when their need for intimacy and social connection goes unmet.
09/05/2024 - The Science of Loneliness

Are some of us hard-wired to feel chronic loneliness? Recent neuroscience research suggests that loneliness is associated with brain-processing patterns that can alter cognitive and social-emotional experiences — the ways in which we understand the world — and affirm our perception of being different or not fitting in with our peers. This belief impairs our ability to sustain social bonds.

“Social interactions rely on a complex orchestration of brain functions, from understanding another person’s point of view, recognizing their emotional state, feeling their emotional pain, and so on. Difficulties with any of these can affect our ability to connect to others,” says Ellen Lee, M.D., associate professor of psychiatry at the University of California San Diego. “The emotional pain and stress of loneliness can also take a toll on our brains.”

Lee was the corresponding author of a systemic review of 41 studies, involving 16,771 adult participants, examining the neurobiology of loneliness. Researchers in those studies used brain imaging and other scans to identify the differences in the brain structure and function of lonely people. The findings showed that some people were hard-wired for loneliness in the same way that some are hard-wired for anxiety.

Loneliness is defined as the emotional discomfort one feels when their need for intimacy and social connection goes unmet.

In the lonely participants, abnormal structure and/or activity was discovered in the prefrontal cortex, which mediates emotional regulation and inhibitory control; the insula, which plays a role in emotional pain and self-awareness; and in other parts of the brain. The review was published in the journal Neuropsychopharmacology in 2021.1

[Test Yourself: How Severe Is Your Loneliness? Take This Quiz]

Lee says it’s possible that brain changes associated with ADHD, depression, and anxiety can lead to feelings of prolonged loneliness because people tend to withdraw from social interactions when they have low mood or other symptoms.

“Researchers are starting to study these links to understand if improving loneliness could be a way to improve these symptoms,” she says.

Lonely Brains Process the World Differently

In a study published in the journal Psychological Science in 2023, researchers discovered that lonely people viewed the world differently from each other and from nonlonely people. Using fMRI scans to examine neural responses to stimuli (videos) and other methods, the researchers also administered a loneliness scale and survey to evaluate the 66 study participants.2

They found that loneliness was associated with structural and functional differences in regions of the brain, and the researchers said their results remained significant even after controlling for individuals’ reported numbers of friends.

“Lonely people process the world idiosyncratically, which may contribute to the reduced sense of being understood that often accompanies loneliness,” the researchers said in the study. “In other words, we found that nonlonely individuals were very similar to each other in their neural responses, whereas lonely individuals were remarkably dissimilar to each other and to their nonlonely peers.”

The researchers said the findings “raise the possibility that being surrounded predominantly by people who view the world differently from oneself may be a risk factor for loneliness (even if one socializes regularly with them).”

Those findings echo the lived experience of many adults with ADHD who report feeling a sense of isolation due to their perceived difference. “I mostly feel like a dolphin in a sea of stingrays,” an ADDitude reader says. “I never meet people with whom I have anything significant in common, and with whom I can forge solid, lasting friendships.”

[Read: How to Make Friends As an Adult With ADHD]

The Evolutionary Function of Loneliness

Stephanie Cacioppo, Ph.D., a behavioral neuroscientist whose research seeks to understand how people experience different emotions, says evolution has sculpted the human brain to respond to biological mechanisms like hunger and thirst. Hunger, she says, is triggered by low blood sugar and motivates us to eat. Thirst helps us find water before we become dehydrated. Pain encourages us to take care of our body.

“Loneliness alerts us to potential threats, and damage to our social body, and in doing so, increases our motivation to bond with others,” says Cacioppo, author of Wired for Love. “It’s the brain’s way of telling you: You’re in social danger, you’re on the periphery of the group, you feel left out, misunderstood, you need protection, inclusion, support, and love. One of the most important things that love can do, it turns out, is shield us from the ravages of chronic loneliness.”

Cacioppo says it’s not uncommon for people to mask in the company of others when they don’t feel a sense of connection.

Masking is totally understandable from a neuroscientific perspective,” she says. “The best solution is to stay authentic. Authenticity is the key to connectivity. Building connections with people while staying true to yourself can be a buffer against loneliness.”

How to Deal with Loneliness

Cacioppo offers several strategies to address chronic loneliness, encapsulated by the acronym G.R.A.C.E.:

Gratitude: Every day, write down five things you truly appreciate. Science shows that expressing gratitude improves emotional wellbeing.

Reciprocity: If you know someone who feels lonely, ask them for help or for advice. Showing respect can give a lonely person a sense of worth and belonging that decreases feelings of isolation.

Altruism: Helping others, and sharing your knowledge, will give you a feeling of self-expansion that is similar to what people experience when they are in a love relationship.

Choice: The tricky thing about loneliness is that, to some extent, it’s self-fulfilling. The more you think you are lonely, the more you are. To break the spiral, shift your mindset and choose to be curious about how you can make meaningful connections.

Enjoy: Smiling and sharing good times (or good news) with people helps reduce loneliness and increase happiness.

How to Deal with Loneliness: Next Steps

View Article Sources

1 Lam JA, Murray ER, Yu KE, Ramsey M, Nguyen TT, Mishra J, Martis B, Thomas ML, Lee EE. Neurobiology of loneliness: a systematic review. Neuropsychopharmacology. 2021 Oct;46(11):1873-1887. doi: 10.1038/s41386-021-01058-7. Epub 2021 Jul 6. PMID: 34230607; PMCID: PMC8258736.
2 Baek, E. C., Hyon, R., López, K., Du, M., Porter, M. A., & Parkinson, C. (2023). Lonely Individuals Process the World in Idiosyncratic Ways. Psychological Science, 34(6), 683-695.

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