According to a recent study, an estimated 10 to 20 percent of adults suffer from loneliness or feelings of isolation. The study focused on the brain’s reaction to loneliness, identifying distinct brain variations offering clues to how loneliness affects us. (1)

Loneliness And The Brain

Headed by a team at McGill University, the study identified neurobiological signatures distinct to lonely people. “We are just beginning to understand the impact of loneliness on the brain,” says Danilo Bzdok, Ph.D., a researcher at the Neuro (Montreal Neurological Institute-Hospital) and the Quebec Artificial Intelligence Institute. “Expanding our knowledge in this area will help us to better appreciate the urgency of reducing loneliness in today’s society.” (1,2)

Loneliness And The Brain’s Health

In hand with research co-lead by Nathan Spreng, Ph.D., and team, their published research paper indicates, “Despite severe consequences on behavior and health, the neural basis of loneliness remains elusive.” (1,2)

The study views the health burden of loneliness as “pervasive.” It is related to health issues including morbidity, hypertension, and immune system dysfunction. From a mental health standpoint, it also increases the risk of suicide and major psychiatric disorders. (1,2)

The risk of cognitive decline as well as dementia can also increase due to loneliness. “A sense of loneliness has also been associated with health risks that are equivalent to or exceed that of obesity or smoking 15 cigarettes daily,” the research explains. (1,2)

Trait Loneliness And The Brain

The study focused on “time-enduring,” or “trait” loneliness. “This is distinct from the amount of time spent alone, or the frequency of social contact,” says the paper. “While there is growing evidence that social connectedness may be associated with brain structure and function … in the current report we directly investigate the neural correlates linked to trait loneliness, that is, the negative subjective experience of social isolation.” (1,2)

A systematic assessment studies the manifestation of trait loneliness in the human brain using magnetic resonance imaging (MRI) data, genetics, and psychological self-assessments. The MRI data of about 40,000 middle-aged and older adult participants were compared between those feeling lonely and those who weren’t. (1,2)

Loneliness And The Brain’s Default Network

The differences in brain manifestations centered around the “default network.” This is “an assembly of higher association areas, which is known to overlap with the human social brain,” according to the paper. Lonely participants had default networks more strongly wired together, with greater volumes of grey matter. (1,2)

Differences were also noted in the fornix which carries signals from the hippocampus to the default network. Lonely participants had a better-preserved structure of the fiber tract of the fornix.  Lonely individuals display stronger functional communication in the default network, and greater microstructural integrity of its fornix pathway,” note the researchers. (1,2)

Imagination And Envisioned Future

“The default network is well-known to be implicated in mental representations of oneself across time and space, including the reconstruction of one’s personal past, prospecting and planning about an envisioned future, imagination, and creative thought as well as stimulating thoughts, places, and events,” according to researchers. “The findings fit with the possibility that the up-regulation of these neural circuits supports mentalizing, reminiscence, and imagination to fill the social void.” (1,2)

The team speculates that their findings could mean increased demands on mental simulation of inner social events occur when lonely people don’t enjoy the social experiences they desire in their lives. (1)

Source:

  1. https://www.genengnews.com/news/scientists-show-what-loneliness-looks-like-in-the-brain/#:~:text=Bzdok%2C%20together%20with%20research%20co,associated%20with%20perceived%20social%20isolation.%E2%80%9D
  2. https://www.nature.com/articles/s41467-020-20039-w