Loneliness And Depression: How The Stress Of Social Isolation Affects Mental Health

In 2023, then-US Surgeon General Vivek Murthy declared loneliness to be an epidemic in the United States. Social isolation and persistent loneliness are serious problems, as they can affect physical and mental health in various ways and may even cause early mortality. 

For decades, researchers have been studying the effects of isolation and loneliness and their links to depression and other conditions, with recent findings shedding even more light on the topic. Here, we will explore statistics about loneliness, the link between loneliness and depression, and how to get help if you're feeling the effects of social isolation. 

What are loneliness and depression?

The American Psychological Association defines loneliness as “affective and cognitive discomfort or uneasiness from being or perceiving oneself to be alone or otherwise solitary.” 

Solitude is the state of being alone, while loneliness is feeling bothered or upset about being alone or feeling disconnected. Some solitude can be healthy and may even feel recharging for many people, but ongoing social isolation and loneliness can lead to negative health effects, since humans are social creatures wired for regular interaction. Also note that it's possible to not be socially isolated but still feel lonely, as the quality and closeness of one's interpersonal connections also matter.

Depression is a common but serious mental health condition. It's thought to be caused by a complex combination of factors, including genetics and environment, and researchers believe loneliness may also put a person at higher risk of developing it. Common symptoms of depression include:

• Persistent low mood
• Loss of interest in activities once enjoyed
• Eating more or less than usual
• Sleeping more or less than usual; poor sleep quality
• Feelings of hopelessness and worthlessness
• Social withdrawal
• Thoughts of self-harm or suicide 

Only a doctor or qualified mental health professional can diagnose an individual with depression. In order for a diagnosis to be considered, symptoms must persist for at least two weeks and must significantly interfere with daily functioning. Depression is considered treatable, usually through a combination of talk therapy, medication, and lifestyle changes. 

The link between loneliness and depression

Researchers have identified links between the psychological aspects of loneliness and depression. It's been understood for some time that social support can be a protective factor against developing depression, while a lack of social support can be a risk factor. However, new research has recently come to light about another factor in the equation: rumination about loneliness.

What is rumination?

A study published by Hong Kong University in January 2025 suggests that it's not just loneliness that may increase a person's risk of depression, but rumination about one’s loneliness. The study defines loneliness as “a gap between desired and actual social connections” and rumination as “repetitive and intrusive negative thoughts and feelings.” 

Ruminating can be thought of as fixating on a negative situation or anxiety in a repetitive way, amplifying your concern and mental distress over time. Rumination is a common symptom in a variety of mental health disorders, including obsessive-compulsive disorder (OCD), generalized anxiety disorder (GAD), and depression. 

How is rumination connected to social isolation, loneliness, and depression?

According to the 2025 study cited above, researchers suggest that rumination may mediate the relationship between loneliness and depression. Their findings indicate that more loneliness may cause more rumination, which may be linked to an increased risk of developing depression as well as increased severity of depressive symptoms. 

Also consider findings from other studies on depression and loneliness that shed more light on how this can become a difficult cycle. For example, a 2021 study suggests that prolonged loneliness may make a person mistrustful of others. This maladaptive social cognition may potentially inhibit social interaction and reinforce negative, ruminative thoughts. There’s also a 2019 study suggesting that a judgmental attitude towards one's thoughts and feelings—which often characterizes rumination—may be linked to depression and anxiety.

When combined, these studies paint a more precise picture of how loneliness and depression may be linked. A person who is lonely may start to fixate on this loneliness and the negative feelings it causes. Over time, their loneliness may make them mistrustful of others, which could cause the few social interactions they engage in to feel negative. This could exacerbate their upset feelings and negative judgments about their loneliness and the emotions it's causing, which could lead to symptoms of depression. In turn, depression may cause further social withdrawal, exacerbating all symptoms. Understanding the complex links in this process may help inform social programs and treatment approaches for both loneliness and depression.

Statistics about loneliness in young people, older adults, and others

There are many statistics available about current levels of loneliness around the world today. Here are some to consider.:

• As of 2024, “30% of adults say they have experienced feelings of loneliness at least once a week over the past year, while 10% say they are lonely every day.”
• According to a Harvard study conducted during the height of the COVID-19 pandemic, 61% of US adults in the 18–25 age group reported being lonely frequently, almost all of the time, or all of the time, compared to 24% of adults ages 55–65.
• In the United States, around 25% of adults report feeling lonelier in 2024 than they did before the COVID-19 pandemic began.
• It’s estimated that around 25% of older adults today experience social isolation, and 5–15% of adolescents experience loneliness.
• A 2024 report from the Centers for Disease Control (CDC) shares that bisexual and transgender individuals are more likely to be lonely than heterosexual and cisgender people, likely because of lived experiences of discrimination.
• The CDC also reports that loneliness and lack of social and emotional support are high among most racial and ethnic minority groups and those with lower education and income levels, likely due to systemic barriers that fragment communities and cause time poverty, among other factors.

Health risks of feelings of loneliness for older adults and others

Loneliness can have serious impacts on a person's overall health and well-being. According to the CDC, some potential effects of prolonged loneliness can include increased risk of cardiovascular disease, stroke, diabetes, dementia, depression, low self-esteem, anxiety, self-harm, suicide, and earlier death. It also notes that young people and older adults may be at increased risk of social isolation and loneliness, and therefore at increased risk of effects like these.

Ways to address social isolation and feelings of loneliness

Addressing social isolation and loneliness may help decrease a person's risk of depression and other health challenges and increase feelings of well-being. Though it can feel overwhelming to address loneliness, it usually helps to start by taking small, positive steps toward connectedness. One example is making the effort to maintain current social connections. Saying hello to a neighbor you used to chat with often, calling a relative you love, or texting a friend you haven't seen in a while could all help you feel more connected and may lead to nourishing time spent with others.

Another strategy for reducing loneliness is to get involved in activities with like-minded people to build quality interpersonal relationships. Volunteer organizations, community mutual aid groups, sports leagues, craft clubs, and book clubs are examples of some activities that might be worth looking into. If going to an event where you don't know anyone seems intimidating, you might start smaller. For example, you could begin regularly spending time in public social spaces to get more comfortable being around people and cultivating small, positive interactions. You might start reading the newspaper at the library every day, walking through the park regularly, or working on a book or a craft at a coffee shop near you each week.

Finally, it can also help to be mindful of your social media use. In some cases, the internet can bring people together, as research suggests that online connections may be able to supplement in-person connections when it comes to reducing feelings of loneliness. However, research also suggests that social media has the potential to exacerbate feelings of loneliness and harmful social comparison. Paying attention to how your social media use makes you feel and limiting it accordingly could be helpful.

Ways to address rumination and stress about loneliness

As suggested by the 2025 study cited above, rumination about loneliness may increase a person's risk of developing depression. That's why addressing rumination can be so important. If you notice that you’re feeling lonely and ruminating about it, it may help to:

• Try a breathing exercise to ground yourself in your body
• Dance, take a brisk walk, or engage in another type of physical activity to boost mood
• Reach out to someone to feel connected and take your mind off of your worries
• Practice positive affirmations, such as “I am worthy of love and connection”
• Listen to a guided meditation to help you focus on the present moment and let distressing thoughts pass you by

If you're struggling to control negative thoughts or emotional distress, you may benefit from connecting with a therapist. We’ll share more about this below.

Treatment options for depression

Symptoms of depression typically won't resolve without treatment, but it is considered a treatable condition with professional support. Many people with depression respond well to talk therapy. Modalities like cognitive behavioral therapy (CBT), which helps people learn to recognize and reframe distorted thoughts, may be especially effective. In some cases, doctors may also prescribe medication in combination with talk therapy. Lifestyle changes like getting enough sleep and exercising regularly may be recommended too.

Seeking mental health support for stress, loneliness, and depression

Meeting with a licensed therapist can be a helpful next step for anyone experiencing loneliness, stress, and/or signs of psychiatric disorders like depression. A therapist can help you understand where negative thoughts may be coming from, teach you techniques to reframe them, and support you in making healthy changes that may help you feel better.

However, not everyone is able to attend in-person therapy sessions, whether due to a lack of providers nearby or barriers to commuting to and from appointments. In such cases, online therapy can be a more convenient option. Platforms like BetterHelp match clients with a licensed therapist according to their needs and preferences as outlined in an onboarding questionnaire. Once matched, you can meet with your therapist virtually from anywhere you have internet, and you can switch providers at any time for no extra cost until you find the right fit.

Research on online therapy for depression and other mental health concerns

A significant body of research from the past several years generally supports the efficacy of online therapy. For example, one study from 2020 suggests that online CBT can be “at least as effective” as in-person therapy for treating depression.

Takeaway

Researchers had previously linked loneliness to mental health risks like depression, but new research has made this connection even clearer. A 2025 study by Hong Kong University suggests that rumination about one's feelings of loneliness may be linked to depression, rather than loneliness on its own contributing to this illness. Addressing social isolation and loneliness can involve reaching out to past or present connections, getting involved in groups related to your interests, and being mindful of social media use. To avoid rumination, you might engage in a breathing exercise or physical activity when you feel these thoughts arising. Meeting with a therapist can also be helpful for addressing these challenges as well as symptoms of depression.