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
DEC 27, 2020
Immunology
Thymus Transplantation?! It Could be Possible!
DEC 27, 2020
Thymus Transplantation?! It Could be Possible!
The thymus is an essential organ of the lymphatic system; it is responsible for developing mature T cells. T c ...
DEC 28, 2020
Cancer
Revealing a Critical Protein Involved in the Pentose Phosphate Pathway in Cancer
DEC 28, 2020
Revealing a Critical Protein Involved in the Pentose Phosphate Pathway in Cancer
The metabolism of cancer has interested scientists in recent decades. Many cancers conduct "normal" metabolism ...
DEC 30, 2020
Drug Discovery & Development
Gene Therapy Cures Mice of Deafness
DEC 30, 2020
Gene Therapy Cures Mice of Deafness
Currently, around half a billion people suffer from hearing loss around the world. In about half of these cases, genetic ...
JAN 01, 2021
Genetics & Genomics
Common Brain Disorder Has a Genetic Influence
JAN 01, 2021
Common Brain Disorder Has a Genetic Influence
It's thought that as many as one in one hundred people are born with a brain disorder known as Chiari 1 malformation, bu ...
JAN 17, 2021
Microbiology
Gut Microbes May Play a Role in Anorexia
JAN 17, 2021
Gut Microbes May Play a Role in Anorexia
Eating disorders like anorexia nervosa and bulimia nervosa are illnesses that involve serious disturbances in eating beh ...
JAN 18, 2021
Microbiology
Bacteria in Sediment is Likely Accelerating Greenland's Meltdown
JAN 18, 2021
Bacteria in Sediment is Likely Accelerating Greenland's Meltdown
For decades, scientists have been sounding the alarm about rising carbon dioxide levels in our planet's atmosphere, and ...
Loading Comments...