McGill University study finds how loneliness affects our health

In a new study held by McGill University, scientists show the effects of loneliness in the brain highlighting how neural 'signature' may reflect our response to feelings of social isolation. The researchers show the importance to understand how isolation affects our health through the study. They discovered a sort of signature in the brains of lonely people that make them distinct in various ways, based on variations in the volume of different brain regions as well as based on how those regions communicate with one another across brain networks.

A team of researchers examined the magnetic resonance imaging (MRI) data, genetics and psychological self-assessments of approximately 40,000 middle-aged and older adults who volunteered to have their information included in the UK Biobank: an open-access database available to health scientists around the world. They then compared the MRI data of participants who reported often feeling lonely with those who did not. The researchers found several differences in the brains of lonely people. These brain manifestations were centred on what is called the default network: a set of brain regions involved in inner thoughts such as reminiscing, future planning, imagining and thinking about others.

Researchers found the default networks of lonely people were more strongly wired together and surprisingly, their grey matter volume in regions of the default network was greater. Nathan Spreng from The Neuro (Montreal Neurological Institute-Hospital) of McGill University and the study's lead author said, "In the absence of desired social experiences, lonely individuals may be biased towards internally-directed thoughts such as reminiscing or imagining social experiences. We know these cognitive abilities are mediated by the default network brain regions."

Loneliness is increasingly being recognised as a major health problem, and previous studies have shown older people who experience loneliness have a higher risk of cognitive decline and dementia. Understanding how loneliness manifests itself in the brain could be key to preventing neurological disease and developing better treatments, according to the study published in the journal Nature Communications.

Danilo Bzdok, a researcher at The Neuro and the Quebec Artificial Intelligence Institute, and the study's senior author said, "We are just beginning to understand the impact of loneliness on the brain. Expanding our knowledge in this area will help us to better appreciate the urgency of reducing loneliness in today's society."