In a world that is more connected than ever, a silent epidemic is taking its toll. Overall, one in three US adults report chronic loneliness — a condition so detrimental that it rivals smoking and obesity with respect to its negative effect on health and well-being. From anxiety and depression to life-threatening conditions like cardiovascular disease, stroke, and Alzheimer’s and Parkinson’s diseases, loneliness is more than an emotion — it’s a serious threat to both the brain and body.
In 2023, a US Surgeon General advisory raised the alarm about the national problem of loneliness and isolation, describing it as an epidemic.
“Given the significant health consequences of loneliness and isolation, we must prioritize building social connection in the same way we have prioritized other critical public health issues such as tobacco, obesity, and substance use disorders. Together, we can build a country that’s healthier, more resilient, less lonely, and more connected,” the report concluded.
But how, exactly, does chronic loneliness affect the physiology and function of the brain? What does the latest research reveal about the link between loneliness and neurologic and psychiatric illness, and what can clinicians do to address the issue?
This news organization spoke to multiple experts in the field to explore these issues.
A Major Risk Factor
Anna Finley, PhD, assistant professor of psychology at North Dakota State University, Fargo, explained that loneliness and social isolation are different entities. Social isolation is an objective measure of the number of people someone interacts with on a regular basis, whereas loneliness is a subjective feeling that occurs when close connections are lacking.
“These two things are not actually as related as you think they would be. People can feel lonely in a crowd or feel well connected with only a few friendships. It’s more about the quality of the connection and the quality of your perception of it. So someone could be in some very supportive relationships but still feel that there’s something missing,” she said in an interview.
So what do we know about how loneliness affects health? Evidence supporting the hypothesis that loneliness is an emerging risk factor for many diseases is steadily building.
Recently, the American Heart Association published a statement summarizing the evidence for a direct association between social isolation and loneliness and coronary heart disease and stroke mortality.
In addition, many studies have shown that individuals experiencing social isolation or loneliness have an increased risk for anxiety and depression, dementia, infectious disease, hospitalization, and all-cause death, even after adjusting for age and many other traditional risk factors.
One study revealed that eliminating loneliness has the potential to prevent nearly 20% of cases of depression in adults aged 50 years or older.
Indu Subramanian, MD, professor of neurology at the University of California, Los Angeles, and colleagues conducted a study involving patients with Parkinson’s disease, which showed that the negative impact of loneliness on disease severity was as significant as the positive effects of 30 minutes of daily exercise.
“The importance of loneliness is under-recognized and undervalued, and it poses a major risk for health outcomes and quality of life,” said Subramanian.
Subramanian noted that loneliness is stigmatizing, causing people to feel unlikable and blame themselves, which prevents them from opening up to doctors or loved ones about their struggle. At the same time, healthcare providers may not think to ask about loneliness or know about potential interventions. She emphasized that much more work is needed to address this issue.