Monday, May 10, 2021

The Science of Loneliness

 From Wired:

Humans rarely experience such extreme social isolation, but studies have shown that even in normal life, increased loneliness has a negative impact on physical and mental health. One review of the science of loneliness found that people with stronger social relationships have a 50 per cent increased likelihood of survival over a set period of time compared with those with weaker social connections. Other studies have linked loneliness to cardiovascular disease, inflammation, and depression.

We’ve known since the 1980s that people who are more socially isolated tend to have worse health, but we still don’t know why loneliness is so closely linked to our health. Is it that isolated people tend to have other risk factors for certain diseases, or is there something about loneliness itself that rearranges the wiring of our brains, slowly wearing away at our health? For loneliness researchers the pandemic has provided an unprecedented natural experiment in the impact that social isolation might have on our brains. As millions of people across the world emerge from months of reduced social contact, a new neuroscience of loneliness is starting to figure out why social relationships are so crucial to our health.

Although the link between loneliness and poor health is well-established, scientists have only recently been able to take the first glimpses of what social isolation looks like in our brains. It’s a discovery that started with a failed experiment. As part of her PhD at Imperial College London, Gillian Matthews was trying to find out how drug addiction affected the connections between specific neurons in a part of the brain called the dorsal raphe nucleus (DRN). Matthews divided the mice she was studying into two groups—one she injected with cocaine, and the other with a saltwater solution—but no matter what she tried, she kept seeing that the DRN neuron connections were growing stronger in both groups of mice.

These new neural connections, Matthews realized, had little to do with drugs. Both groups of mice had been isolated for 24 hours before the start of the experiment. What Matthews was seeing was the effect that social isolation had on the brains she was studying. This accidental discovery opened up a new way of thinking about loneliness—if we could see the traces of social isolation in the brains of mice, it meant that loneliness didn’t just describe a state in the outside world, it could also point to something on the inside too. (Read more.)


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