NOV 24, 2015 5:03 PM PST

How Loneliness Can Make You Sick

WRITTEN BY: Julianne Chiaet
Being alone isn’t the same thing as being lonely. Many people who enjoy being alone don't grapple with loneliness. When a person suffers loneliness, they feel disconnected and experience perceived social isolation. 

Perceived social isolation is a proven risk factor for chronic illness and mortality. Yet, scientists had not previously understood why.
 
Older people who report loneliness suffer more illnesses and earlier deaths

Now, a new study reveals the molecular mechanisms behind loneliness leading to illness. Researchers led by psychologist John Cacioppo found that loneliness leads to higher levels of the fight-or-flight neurotransmitter, norepinephrine, which affects the production white blood cells. The study was published on November 23 in Proceedings of the National Academy of Sciences.

Cacioppo previously found that the immune system becomes less effective in lonely people over time. The study showed perceived social isolation evoked a "conserved transcriptional response to adversity" (CTRA). The gene expression CTRA is identified by two significant changes: There is an increased expression of genes involved in inflammation and a decreased expression of genes involved in the immune system.

In his new study, Cacioppo and his research team wanted to see if perceived social isolation causes white blood cells to activate CTRA gene expression. They tracked a sample of 141 older adults from the Chicago Health, Aging, and Social Relations Study. The scientists analyzed white blood cell transcriptome surveys for each participant during study years 5, 7, 8, 9, and 10. In total, they analyzed 412 surveys. The data indicated that loneliness predicted CTRA gene expression measured a year or more later. What’s more surprising - CTRA expression predicted loneliness measured a year or more later.

This suggests that loneliness and CTRA gene expression have a reciprocal relationship. The reciprocal relationship between loneliness and CTRA gene expression could mean CTRA propagates loneliness and contributes to its related diseases.
 

 
The research team then looked at the cellular processes in socially isolated rhesus macaque monkeys. They chose rhesus macaque monkeys because they are a highly social primate species. The scientists established a standard to distinguish monkeys who were lonely versus controls (social monkeys). Like the lonely humans, CTRA gene expression was increased and there were higher levels of norepinephrine. Norepinephrine can stimulate blood stem cells in bone marrow to make more of a particular kind of immune cells. These immune cells, called immature monocytes, show high levels of inflammatory gene expression and low levels of antiviral gene expression. Thus, there was an increase in CTRA gene expression due to the greater output of immature monocytes.

To test the physiological effects, the researchers exposed the animals to the monkey version of HIV, called SIV. The virus grew faster in the brain and blood of the lonely monkeys versus the controls. 

The data suggests loneliness causes increased levels of norepinephrine, which in turn increases the production of immature monocytes, which causes CTRA gene expression. 

Like an illness, loneliness needs to be managed. It’s not just a feeling. The team plans to continue research on loneliness and how the effects of loneliness can be prevented in the elderly.

Sources: PDF of study via University of ChicagoPress Release via EurekAlert!, Medical Daily 
 
About the Author
  • Julianne (@JuliChiaet) covers health and medicine for LabRoots. Her work has been published in The Daily Beast, Scientific American, and MailOnline. While primarily a science journalist, she has also covered culture and Japanese organized crime. She is the New York Board Representative for the Asian American Journalists Association (AAJA). • To read more of her writing, or to send her a message, go to Jchiaet.com
You May Also Like
MAR 16, 2021
Clinical & Molecular DX
A Blood Test for Predicting if You'll Live to 100
MAR 16, 2021
A Blood Test for Predicting if You'll Live to 100
In 2012, a United Nations report estimated that there are over 316,000 people worldwide over the age of 100. What’ ...
MAR 18, 2021
Neuroscience
Pregnancy Alters the Stress Response in Surprising Ways
MAR 18, 2021
Pregnancy Alters the Stress Response in Surprising Ways
Researchers from Ohio State University have found that the stress response works in unexpected ways in pregnant mice. Th ...
MAR 28, 2021
Cell & Molecular Biology
Understanding How Cold-Induced Tooth Pain Happens
MAR 28, 2021
Understanding How Cold-Induced Tooth Pain Happens
Our teeth do a lot of work, and they may become sensitive to cold as the gums erode due to aging or because they have an ...
APR 08, 2021
Clinical & Molecular DX
Marijuana Versus Tobacco: Which Is Worse for Your Lungs?
APR 08, 2021
Marijuana Versus Tobacco: Which Is Worse for Your Lungs?
Canadian researchers have observed that individuals who smoke marijuana are more at risk than tobacco cigarette smokers ...
APR 05, 2021
Cannabis Sciences
Can Smoking Cannabis Cause Lung Cancer?
APR 05, 2021
Can Smoking Cannabis Cause Lung Cancer?
So far, there is no firm consensus on whether smoking cannabis can cause lung cancer. As cannabis smoke contains many si ...
APR 11, 2021
Genetics & Genomics
Trial Shows Personalized Cancer Vaccines are Safe
APR 11, 2021
Trial Shows Personalized Cancer Vaccines are Safe
Vaccines are mostly known as tools to prevent illness. But cancer vaccines are a bit different, and aim to treat existin ...
Loading Comments...