.png)
.png){kind=small}
April 2024
Researcher: Carissa Taruna
Editor: Alice Pham
Breaking out of a bout of loneliness is difficult for most people, and when acute loneliness becomes chronic, it can greatly impact health. According to a report by Vivek Murthy, the US surgeon general, chronic loneliness can be as harmful as obesity, physical inactivity, and smoking. Depression, dementia, cardiovascular disease, and even early death have all been linked to this condition. In a 2023 poll conducted by the social media firm Meta, along with a group of academic advisers, around one-quarter of adults worldwide report experiencing loneliness. In the same year, the World Health Organization launched a campaign to address loneliness, calling it a “pressing health threat.”
Why does feeling alone lead to poor health? In recent years, researchers have started to uncover the neurological processes that lead to the breakdown of the human body when social needs are not fulfilled. Additionally, preliminary findings indicate that loneliness may affect various brain functions, including volume and neuronal connections, but the picture is still far from complete.
According to University College London psychiatrist Andrew Sommerlad, loneliness is more than just social separation; it's the sense of dissatisfaction with one's social relationships. The implications of loneliness are significant and wide-ranging, impacting both mental and physical health. Loneliness has been linked to unexpected illnesses such as high blood pressure and immune system malfunction, as well as depression and suicide risk. Moreover, studies have even shown a correlation between dementia and loneliness, suggesting that lonely people have a markedly increased risk of developing this neurological illness.
Loneliness may impair a person's ability to sleep, release stress hormones at higher levels, and increase susceptibility to infections, among other physiological consequences. However, cognitive neuroscientist Livia Tomova of Cardiff University in the UK warns that separating the causes of loneliness from its effects is challenging due to the interaction between these factors. Do certain people have brain characteristics that make them more vulnerable to loneliness, or do people's brains start acting differently when they experience loneliness? "It's difficult to determine which is true," she explains.
Loneliness eats at you. Recent research delves into the neurological effects of loneliness. According to cognitive neuroscientist Laetitia Mwilambwe-Tshilobo from Princeton University, lonely individuals perceive the world differently. In a 2023 study, participants watched various videos while undergoing magnetic resonance imaging. Non-lonely individuals exhibited similar neural responses, whereas lonely participants showed diverse responses, both from each other and from the non-lonely group. This suggests that lonely individuals may focus on different aspects of situations, leading them to perceive themselves as separate from their peers.
Moreover, Mwilambwe-Tshilobo suggests that loneliness may worsen over time, creating a self-reinforcing cycle. This perception of loneliness leads individuals to interpret their social world negatively, driving them further away. Studies suggest this effect can spread through social networks, making loneliness contagious.
Historically, staying connected to others was crucial for human survival. Temporary loneliness likely evolved to motivate people to seek company, similar to how hunger motivates individuals to seek food and water. Research shows parallels between hunger and loneliness at the physiological level. Brain imaging studies reveal common activation in the substantia nigra, a region associated with motivation when hungry individuals see food and lonely individuals see social interactions. Loneliness also affects how the brain processes rewards making humans more responsive, as shown in a study isolating adolescents and testing their responsiveness to monetary rewards.
Loneliness is linked to high levels of stress hormones called glucocorticoids. Chronic loneliness elevates these hormones, which could potentially contribute to conditions like dementia. Stress may accelerate brain aging, though further research is needed. Loneliness may also deprive individuals of the mental stimulation provided by social interactions, as they maintain neural connections which reduces the risk of cognitive decline associated with loneliness.
Researchers investigating the neurological foundations of loneliness and how it relates to dementia have discovered that older people who experience loneliness have altered brain connections, especially in the default network. Older lonely people have fewer connections between the default network and the visual system than younger people, which may indicate that they can lessen their loneliness by reminiscing on previous social interactions. The association between solid default networks and neurodegeneration in conditions like Alzheimer's disease is called into doubt by this changed connectivity.
Potential Solutions: Increasing access to social activities, such as communal living, can ease loneliness, notes Sommerlad. Researchers are also exploring direct interventions like exercise to target the neural mechanisms of loneliness. Benedyk and colleagues found that walking for an hour reversed feelings of loneliness in some individuals since exercise disrupts rumination, especially in those with high connectivity in their default networks, and fosters social interaction. Chaklos leads a community walking program in Boston, where participants chat and stroll together, providing a mood boost and alleviating loneliness.
References
Sidik, S. M. (2024) Why loneliness is bad for your health, Nature News. Nature Publishing Group. Available at: https://www.nature.com/articles/d41586-024-00900-4 (Accessed: 6 April 2024).
Comments