Scientists from the University of Chicago found how feeling alone can have a negative effect on health.
They found loneliness can lead to fight-or-flight stress signaling, which can ultimately affect the production of white blood cells.
The research is published in the Proceedings of the National Academy of Sciences.
In the study, the team examined loneliness in both humans and rhesus macaques, a highly social primate species.
The human participants were in the Chicago Health, Aging, and Social Relations Study, a longitudinal study that began in 2002 with adults aged 50-68.
Previous research identified a link between loneliness and a phenomenon they called “conserved transcriptional response to adversity” or CTRA.
This response is characterized by an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses.
Essentially, lonely people had a less effective immune response and more inflammation than non-lonely people.
In the study, the team examined gene expression in leukocytes, cells of the immune system that are involved in protecting the body against bacteria and viruses.
As expected, the leukocytes of lonely humans and macaques showed the effects of CTRA—an increased expression of genes involved in inflammation and a decreased expression of genes involved in antiviral responses.
But the team also revealed several important new pieces of information about loneliness’ effect on the body.
They found that loneliness predicted future CTRA gene expression measured a year or more later. Interestingly, CTRA gene expression also predicted loneliness measured a year or more later.
Leukocyte gene expression and loneliness appear to have a reciprocal relationship, suggesting that each can help propagate the other over time.
These results were specific to loneliness and could not be explained by depression, stress, or social support.
The team also found loneliness linked to higher levels of the fight-or-flight neurotransmitter, norepinephrine. It’s released into the blood as a stress hormone when the brain perceives that a stressful event has occurred.
Finally, the researchers “lonely like” monkeys had simian immunodeficiency virus (the monkey version of HIV) that grows faster in both blood and brain.
Taken together, these findings support a mechanistic model in which loneliness results in fight-or-flight stress signaling, which increases the production of immature monocytes, leading to up-regulation of inflammatory genes and impaired anti-viral responses.
The “danger signals” activated in the brain by loneliness ultimately affect the production of white blood cells. The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks.
Sign up for our newsletter for more information about this topic.
If you care about mental health, please read studies about 6 daily habits to reduce stress & anxiety, and this daily supplement may help lower anxiety.
For more information about mental health, please see recent studies that Ketamine strongly reduces depression and suicide, and results showing people with these mental diseases have lower COVID-19 risk.
Copyright © 2022 Knowridge Science Report. All rights reserved.
