A new study published in PLOS One looked at the impact of loneliness on depression, mental health, and physical well-being.
“Our study investigates how loneliness, measured as the subjective feeling of social disconnection, predicts poor mental and physical health outcomes,” study author Oluwasegun Akinyemi told us. “Specifically, we examined whether individuals who feel lonely more often are more likely to experience clinical depression, more frequent days of poor mental health, and more frequent days of poor physical health. Our goal was to estimate this relationship using rigorous statistical methods and a nationally representative dataset, in order to inform public health responses.”
The researchers hypothesized that higher levels of loneliness would be associated with significantly worse mental and physical health outcomes, particularly an increased likelihood of depression. They also suspected that these effects might vary across demographic lines such as age, race, and gender, based on prior evidence suggesting differences in the experience and consequences of loneliness.
“Loneliness is often described as a silent epidemic,” Akinyemi told us. “It cuts across age, race, and social status, and yet it remains under-recognized in public health discourse. During and after the COVID-19 pandemic, I observed how isolation took a toll on individuals’ emotional and physical well-being. This study was born out of a desire to quantify that toll and to provide robust, population-level data that can help design targeted interventions.”
The research team analyzed data from over 47,000 U.S. adults who participated in the Behavioral Risk Factor Surveillance System (BRFSS) between 2016 and 2023. Using a statistical technique called inverse probability weighting, the researchers estimated the average treatment effects of loneliness on health outcomes, adjusting for a range of demographic and socioeconomic variables. This approach simulates a randomized design and helps strengthen the causal interpretation of the findings.
“The results were striking,” Akinyemi told us. “People who reported always feeling lonely had a 50.2% likelihood of clinical depression, compared to just 9.7% among those who never felt lonely.”
The study also found an average of 10.9 more poor mental health days per month and about five additional poor physical health days each month.
While this study sheds light on loneliness as a health risk, it also highlights resilience in some populations. For instance, Black and Hispanic individuals, despite reporting high loneliness levels, showed lower predicted probabilities of depression than White peers.
“This points to cultural or social protective factors that should be better understood and possibly scaled,” Akinyemi told us. “I hope this work inspires deeper conversations and concrete actions around the mental and physical toll of loneliness in our society.”
The research team also found significant disparities. For example, women reported more poor mental health days than men, and older adults had more poor physical health days regardless of loneliness level.
“While we anticipated a strong link between loneliness and depression, the magnitude of the association was surprising,” Akinyemi told us. “That over 50% of those who are always lonely report being clinically depressed is a deeply concerning statistic. It underscores that loneliness is not just an emotional experience, it has real, measurable health consequences.”
The implications are both urgent and actionable according to Akinyemi who believes loneliness should be screened for in primary care settings just like high blood pressure or cholesterol are screened.
“Social prescribing, connecting individuals to community resources, support groups, or recreational activities, should become part of routine healthcare,” Akinyemi told us. “We also need public policies that promote social infrastructure, especially in underserved communities where loneliness may be compounded by other structural disadvantages.”