Insufficient Social Interaction Proves Hazardous, Dementia Risk Can Rise 50 Per Cent
Loneliness and weak social relationships have been found to have adverse impacts not only on mental health but also on the risk of dementia. Several studies show that people with weak social relationships or those experiencing social isolation have a higher likelihood of experiencing cognitive decline in old age.
This information was reported by National Geographic, which reviewed various studies examining the relationship between loneliness, social vulnerability, and dementia risk in older people.
Dementia is a condition characterised by a decline in the ability to think, remember, and make decisions. One of the most common forms of dementia is Alzheimer’s disease, which gradually damages memory capacity and brain function.
A 2025 study estimates that a person has approximately a 42 per cent likelihood of being diagnosed with dementia after age 55. As people age, they experience not only physical decline such as weakening muscles or increased risk of falls, but can also experience what is known as social vulnerability.
Social vulnerability occurs when a person has fewer social relationships, rarely interacts with others, or no longer has people they can rely on in their life.
According to clinical psychologist Suraj Samtani from the Centre for Healthy Brain Ageing at the University of New South Wales, Australia, this condition is not only related to feelings of loneliness. Social vulnerability also includes diminished friendship networks, increasingly limited emotional relationships, and minimal social support.
Several studies show that good social relationships can help maintain brain health. In a 2023 meta-analysis involving 13 studies and almost 40,000 respondents, researchers found that people with strong social relationships had dementia rates about half as high as those with poor social relationships.
This finding reinforces the view that humans are inherently social beings who require interaction with others to maintain both mental and cognitive health. Even in dementia patients, good social relationships can help slow the decline of cognitive function.
To understand the relationship between social vulnerability and dementia, researchers analysed data over 12 years from 851 older people aged over 70 who had not experienced dementia at the beginning of the study.
In this research, scientists used several methods to assess participants’ level of social vulnerability. They asked various questions regarding social activities, the frequency of meeting other people in person, levels of loneliness, and financial conditions.
The analysis results showed that people who were classified as socially vulnerable had approximately 50 per cent higher risk of dementia compared with those who had stronger social relationships.
Experts also found that the relationship between loneliness and dementia is bidirectional. Social vulnerability can increase the risk of cognitive decline, but cognitive impairment can also cause a person to withdraw further from their social environment.
In the early stages of dementia, many people lose confidence when interacting because they fear forgetting words or being unable to follow conversations. This sense of embarrassment and anxiety often leads them to reduce social interaction. As a result, their friendship networks narrow and loneliness worsens.