New research shows how loneliness impacts brain structure

brain structure, the neuro
© Emanuelo Kvartalo

In a year of COVID-19-related death and worry, loneliness has been an accompanying sensation, constant and stubborn – now, scientists believe they know how loneliness changes brain structure

When it comes to loneliness, every dictionary describes the feeling as the absence of friends and being aware of missing people. The second explanation describes a remote or disconnected place. Both describe the way that highly vulnerable people have been living for months now.

When the first UK lockdown was announced in March, a sense of unease struck most people I know. The stay-at-home directive was asking the societal fabric of the country to change and shift, in a way it had forgotten to do. The pandemic is framed in the language of war by PM Boris Johnson, but the UK hasn’t been under attack since 1945.

No government official warned us about what could happen to the lonely people.

In the UK, half a million older people go atleast five or six days a week without seeing or speaking to anyone at all. The simple, small pleasure of talking to the cashier about the weather was lost to them. Walks were limited to one a day in the first UK lockdown, rendering households static for the majority of those spring days. For those without gardens or access to outdoor spaces, this feeling of stillness was tripled.

The Mill spoke to people who had isolated throughout the pandemic. Mick, a 67 year old man who had left his house twice since March, said: “I live alone and I’ve spent most of my life alone.”

Loneliness, a risk to life itself?

In 2016 to 2017, one in twenty adults said that they were often or always lonely. The loneliness that some people feel can put their mental health at risk, and in some cases, their lives.

In the wake of public fixation on this fast-spreading virus, many people lost the protection of being witnessed. When we spoke to Ed O’Donovan, Head of Protection at Frontline Defenders, he said that people who were already struggling pre-pandemic fell into the further tragedy of isolation and loneliness: “We feel that Indigenous communities are now much more isolated. Despite situations of lockdown or curfew, land development activities have continued to take place in the community and left those people much more vulnerable than before, because they don’t have access to the help.”

People who experience domestic violence were now dangerously isolated. The routines that broke up long hours of being in unstable environments disappeared overnight, for thousands of people at risk. Family law barrister Paula Rhone-Adrien asked for global Governments to consider extra funds to rehouse trapped women to hotels, even as a temporary reprieve.

Writing in April, she said: “In Hubei province, the heart of the initial coronavirus outbreak, domestic abuse reports to local police more than tripled in just one county alone. There was a rise of between at least 40% to 50% in domestic abuse complaints identified by Adriana Mello, a Rio de Janeiro judge in Brazil specialising in domestic violence.”

While trauma has been proven to change the way humans respond to subsequent stresses, what about loneliness as a health determinant? A team of Canadian neuroscience researchers set out to answer that increasingly relevant public health question.

No social experiences, more introspection

“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,” says Nathan Spreng from The Neuro (Montreal Neurological Institute-Hospital) of McGill University, and the study’s lead author.

“So this heightened focus on self-reflection, and possibly imagined social experiences, would naturally engage the memory-based functions of the default network.”

What did the research team find out?

Using MRI data, genetics, and self-assessments, the team worked with 40,000 middle-aged and older adults. They found that there were key differences in the brains of lonely people.

In the human brain, there are a set of regions known as the default network. The default network is where inner thoughts like reminiscing, future planning, imagining and thinking about others happens. The team saw that the default networks of lonely people were “more strongly wired together”. At the same time, their grey matter volume in the same place was also stronger.

The fornix is a bundle of nerve fibres that carries signals from the hippocampus to the default network. It is thought to play a key role in memory, specifically recall of long-term memory like details from past events and the regulation of episodic memories.

The fornix of lonely people was interestingly better preserved. Does this mean that loneliness gives you a stronger memory and introspective behaviours? This is unclear, and at this stage in the research, it would be irresponsible to say so in a concrete way. But if we knew, it would be easier to treat neurological diseases and to make a case for treating loneliness as an increasingly serious public health situation. Danilo Bzdok, a researcher at The Neuro and the Quebec Artificial Intelligence Institute, and the study’s senior author, commented:

“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.”

Read the full study here. 

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