How Isolation Affects Brain Disease

Chronic social isolation directly leads to psychological stress and depression, and especially for older adults, this can be a significant risk factor for developing dementia, including Alzheimer’s. Research continues to explore the relationship between the emotional stress of social isolation and physical neurodegeneration, but there is an overlap in psychological and neurological findings. It’s important to be aware of the negative effects that sustained social isolation can have on people, including loved ones. Working to maintain regular contact and interaction with other people not only helps to make life more fulfilling, but it also exercises mental functioning and improves resilience against dementia. 

  Social Isolation and Loneliness  The term “social isolation” is often used interchangeably with “loneliness,” but these are technically different concepts. Loneliness is subjective. It describes how people perceive their own circumstances if they feel they lack closeness or fulfilling connections with others. It is an emotional experience, but a powerful one. By contrast, social isolation is objective and measurable. It refers to having an extremely limited quantity of relationships, accounting for factors such as social network sizes, marital status, living arrangements, and opportunities for engagement within a community. Socially isolated people often live alone and have little communication with family members, friends, colleagues, or other acquaintances. The two states of being often coincide but don’t always overlap. For example, people can feel lonely in a crowd or experience fulfillment in solitude.  Social isolation and loneliness are extremely widespread problems in the United States. According to the Centers for Disease Control and Prevention, about 1 in 4 adults report not having social and emotional support, and 1 in 3 report feeling lonely.¹ Adults over the age of 65 are particularly susceptible to social isolation, and the incidence of cognitive decline, memory impairment, or dementia is higher among those who report feeling lonely. Conversely, seniors who are more socially integrated with others tend to be more resilient to processes affecting brain function, including dementia.²  Social Isolation and Dementia Risk



The link between social isolation and dementia risk is complex, and the precise mechanisms for these effects are not yet fully understood. However, chronic social isolation is a major source of stress that can lead to an increased risk of vascular and neurological diseases, and it has been found to increase morbidity and mortality rates after events such as a heart attack or stroke.³ It can also cause depression and an associated lack of physical activity, which are other risk factors for dementia. Chronic loneliness coincides with higher incidences of smoking and heavy drinking, which are further risk factors. One study suggested that social isolation can increase a person’s risk of dementia by about 60 percent,⁴ but more studies are needed to establish a reliable consensus.



  Just as social isolation is an established risk factor for dementia, the reverse is also true. The symptoms of dementia can lead to further isolation. For example, individuals experiencing memory issues often feel embarrassment, frustration, or shame about these problems and start withdrawing from their social circle. Or their relatives and friends might start distancing themselves—intentionally or unintentionally—due to these symptoms. 



But besides risk factors, there might be a more direct biological link between social isolation and dementia. Studies are now focusing on the possible connection between social isolation and biological systems, specifically the neuroendocrine or hypothalamic-pituitary-adrenal (HPA) axis, the autonomic nervous system (ANS), and the immune system. Each of these systems could play a role in the biological process leading to increased dementia risk for socially isolated individuals, and it’s plausible that drug therapies targeting one of these areas might be effective in helping to mediate this risk.⁵  In fact, two recipients of the American Brain Foundation’s 2025 Next Generation Research grants, Dr. Deborah Rose and Dr. Giovanna Pilonieta, are currently conducting studies in related areas. Dr. Rose is researching the role of chronic stress on the HPA axis and how this may accelerate cognitive decline, particularly among marginalized populations affected by the trauma of adverse childhood experiences. Dr. Pilonieta is researching how modifiable health behaviors contribute to cognitive decline and increased risk for Alzheimer’s disease. Both studies are funded in partnership with the McKnight Brain Research Foundation, which is specifically dedicated to supporting studies on the effects of age-related cognitive decline and memory loss. 

In most cases, social isolation is a modifiable factor, and it can be prevented or resolved through increased social outreach and inclusion. Given the epidemic of loneliness affecting millions of Americans, it’s probably safe to say that each of us could do more to stay in contact with family friends, spend more time together, build more inclusive communities, and reach out to help those in need.



How to Help Social contact is a natural antidote for social isolation, and it helps to increase resilience against dementia. Having frequent friendly interactions with other people sustains mental and emotional health, improves the brain’s ability to cope with disease, reduces stress, and presents opportunities to promote healthy behaviors like exercise. Staying socially active and having regular conversations with other people is good for maintaining cognitive function and communication skills, including listening, speaking, expressing ideas clearly, and recalling relevant details.   If you feel socially isolated or you would like to help someone else who is, getting involved in group activities is a great way to start spending more time around others. For example, consider adult education classes or other learning opportunities, arts and crafts sessions, book clubs or hobby groups, playing a musical instrument or singing, starting a group to go walking or hiking in nature or play a sport (which has the added health benefit of regular exercise), or volunteering. 

The organization UsAgainstAlzheimer’s provides some helpful reminders about social isolation⁶: 

* Understand the link between social isolation and dementia. Remember that social isolation has a negative effect on brain health. It’s important to engage with other people regularly to keep your brain stimulated and healthy, which can reduce the risk of Alzheimer’s disease and other dementia. 

* Know the risk factors of social isolation. Remember that major life events and health issues can lead to social isolation, especially for older adults. This could include the loss of a loved one or close friend, moving to a new home, retiring, or facing new challenges like hearing loss that makes communication more difficult. 

* Ask questions to identify social isolation. Ask yourself how many times per week do you talk on the telephone with family, friends, or neighbors? How often do you get together with them in person? How often do you attend scheduled gatherings, be they community organizations, religious services, or clubs? 

* Be aware of the shame of social isolation. Besides the loneliness that often coincides with social isolation, the experience can also cause some people to feel ashamed of their situation. If you feel isolated, know that many other people face the same challenges, and start thinking about who you could contact. If your loved one is isolated, please try to stay in touch regularly. Acknowledge their emotions and let them know you want to help. 

For someone who has been experiencing social isolation for a while, it might seem intimidating to reach out to others to make new friends or rebuild social connections. Extended social isolation can erode self-esteem and self-confidence. If you’re currently experiencing this, please know that your feelings are valid, and that you’re inherently worthy of having other people in your life who like you and care about you. There is also nothing wrong with contacting a professional, such as a therapist or counsellor, who might be able to offer guidance on healthy ways to reconnect with friends and family or make new acquaintances. Positive social connections are important for mental and neurological health, but they are also important for our general well-being. 



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