You Can Die From Not Having Friends, Says New Research

Being lonely is deadlier than originally thought. Psychologist Barbara Sahakian tells us why.

By Mark Travers, Ph.D. | July 7, 2022

A new study conducted at the University of Cambridge, Fudan University, and the University of Warwick examines the link between loneliness and the development of mental health and neurodegenerative disorders.

I recently spoke with psychologist Barbara Sahakian about loneliness and the effects it can have on our brain. Here is a summary of our conversation.

What inspired you to investigate the impact of social isolation and loneliness on dementia?

Social isolation and loneliness are prevalent in both males and females and across all ages and cultures.

Both social isolation and loneliness were made worse by the COVID-19 pandemic lockdowns. We wanted to get a fuller understanding of the associations between social isolation and loneliness with respect to the risk of dementia.

We also wanted to understand how an association between social isolation and later dementia might relate to differences in structural brain measures and cognitive ones.

Understanding these relationships is important for public health and other initiatives that can be implemented to help reduce an individual's risk of dementia.

Can you give a brief description of how social isolation contributes to dementia?

We found that socially isolated individuals had lower brain gray matter volumes, including in the hippocampus, an area important for learning and memory. The hippocampus is also one of the earliest brain regions to show the neuropathological changes in people with Alzheimer's disease.

We also discovered that people who were socially isolated were 26% more likely to develop dementia than those who were not socially isolated.

What behaviors can one undertake in order to prevent potential dementia caused by social isolation and loneliness?

It is important that individuals do not get socially isolated at any age.

From our study, we now know that social isolation carries an increased risk of dementia in older adults. Furthermore, social isolation detracts from well-being.

The UK Government Foresight Project on Mental Capital and well-being discussed five evidence-based ways to well-being and one was to stay socially connected. Therefore, people should make an effort to stay socially connected and to have good social support systems through family and friends.

They can also do this through volunteering to help a favorite charity, joining choirs, or other group or community activities.

It is important that general practitioners and other health professionals, including neurologists, ask older patients whether they are socially isolated.

In our study we used three questions: Do you live alone? Do you participate in social activities less than once a week? Do you have social contact less than once a month?

Why do you think social isolation and loneliness are so impactful on psychological and subsequent neurological health?

Humans are social animals and therefore social isolation can have a significant negative impact on our brains, cognition, and well-being.

In speculating about ways that social isolation may exert its effects, several possibilities come to mind:

  • First, if you are socially isolated, then you have no one immediately available to help with solving problems or difficulties that you encounter in daily life. This lack of support can cause chronic stress and we know that chronic stress has detrimental effects on the brain, including the hippocampus, on cognition, and on mental health. It also affects the immune system.
  • Second, Martin Orrell and I wrote an article on "Use it or lose it" published in the British Medical Journal (BMJ), where we emphasized that it is important to keep your mind active throughout life. Similarly to keeping your body fit for good physical health, you have to keep your brain fit for good cognition and mental health. Eleanor McGuire and colleagues showed in their study with taxi drivers that the more the learned and remembered routes and street locations, the more the volume of the hippocampus increased. Therefore, if we are socially isolated and not engaging in discussions regularly, our language abilities and other cognitive processes, such as attention and memory, may diminish. In addition, the reward system in the brain is activated when we engage in positive social interactions, but if an individual is socially isolated, this may not occur.

In our study, we found that the effects of loneliness were primarily related to depression.

Did you find any sex (male/female) differences or other demographic differences?

In the subgroup analysis that we conducted, we found that the association between social isolation and dementia was consistent across males and females.

How does your research connect with, and inform, other research on the consequences of loneliness and social isolation?

To our knowledge, this is the largest-scale study in terms of the number of participants which investigates the associations of social isolation and loneliness with later dementia.

Our study also carefully controlled for possible confounding factors and included brain structural MRI data, cognitive data, and genetic measures.

Therefore, our study was able to clearly demonstrate that social isolation is a risk factor for dementia that is independent of loneliness and many other covariates.

How might your research inform clinical efforts to improve the prevention of neurodegenerative disorders such as dementia?

Fortunately, if we prevent social isolation in older adults, we can reduce the risk of dementia. Since social isolation is a modifiable risk factor, it is important that governments, health providers, and society act to prevent individuals from becoming socially isolated.

Since the effects of loneliness are strongly related to depression, it is important for general practitioners and psychiatrists to assess loneliness and depression in adults in middle-aged and older adults, as there are effective pharmacological and psychotherapeutic strategies such as:

Do you have plans for follow-up research? Where would you like to see research on loneliness and dementia go in the future?

We would like to understand more about the underlying mechanisms involved in the increased risk of dementia by social isolation.

We are also very interested in knowing more about the effects of social isolation and loneliness on the brain, cognition, and well-being in adolescents.