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
JUN 10, 2020
Cannabis Sciences
JUN 10, 2020
Should We Be Concerned About Cannabis Poisoning in Minors?
The Canadian federal government began legalizing aspects of recreational marijuana use in October 2018, so researchers a ...
JUN 13, 2020
Microbiology
JUN 13, 2020
New Spikes in COVID-19 Cases in Eight States and China
COVID-19 cases have been rising in several states, and China has identified a new outbreak.
JUN 14, 2020
Chemistry & Physics
JUN 14, 2020
Why Are There So Few Black People in STEM?
On June 10th, 2020, thousands of STEM scientists and organizations around the world went on strike to protest systemic r ...
JUN 25, 2020
Cardiology
JUN 25, 2020
Using RNA to Predict Acute Ischemic Strokes
Strokes are a leading cause of death and long term-disability across the globe. Ischemic strokes (IS) or acute ischemic ...
JUL 05, 2020
Genetics & Genomics
JUL 05, 2020
Two Deaths Occur During Gene Therapy Trial
There is great promise, as well as serious risks in gene therapy. Many diseases can be traced back to an error or mutati ...
JUL 05, 2020
Neuroscience
JUL 05, 2020
Iron Build-up in Brain Linked to Alzheimer's
Researchers from the Medical University of Graz in Austria have found a link between the build-up of iron in the brain&# ...
Loading Comments...