Introduction

Loneliness has been called a global epidemic in recent years, and for good reason. In 2024, the U.S. Surgeon General declared an “epidemic of loneliness,” noting that lack of social connection carries health risks as deadly as smoking 15 cigarettes a day2. The World Health Organization’s Commission on Social Connection reported that about one in six people worldwide experiences loneliness, with rates highest among teenagers (about 20% of 13–17 year olds) and gradually declining in older age34. It might surprise many that young people often feel lonelier than the elderly. We tend to picture an isolated old man or woman when we think of loneliness, but surveys show adolescents and young adults reporting the most intense loneliness, despite being constantly “connected” via smartphones56. This is one of many paradoxes about loneliness that we will explore.

First, let’s clarify what loneliness actually is. Loneliness is not simply being alone. One can be alone and feel perfectly content, or conversely, feel lonely in a crowd of people. Psychologists define loneliness as a subjective feeling a distressing gap between the social connections you desire and those you feel you have7. In other words, loneliness is the pain we feel when our relationships don’t meet our need for intimacy, belonging, or understanding. It’s possible to have many people around you yet still feel that disconnect. By contrast, social isolation is an objective state having few people to interact with regularly7. An elderly person living alone might be socially isolated, but if they have sufficient meaningful contact or are content with solitude, they might not feel lonely. Meanwhile, a teenager with hundreds of online “friends” may feel deeply lonely if those connections lack genuine intimacy. Throughout this book, keep in mind this crucial distinction: loneliness is about quality, not quantity, of relationships8. It’s a signal from our psyche that something is missing in our relational world.

Loneliness comes in different flavors. Researchers often describe three dimensions of loneliness: emotional, social, and existential910. Emotional loneliness is the ache of missing a close, intimate bond with someone for example, lacking a confidant or life partner. You might have many acquaintances, but still feel a deep emptiness because no one truly knows you. It’s the kind of loneliness that strikes even when you’re not physically alone: “I am with people, but I have no one to share my heart with.” Emotional loneliness can come from the loss or absence of a close relationship, such as grieving a loved one or longing for a best friend or romantic partner11. Social loneliness, on the other hand, stems from lacking a broader social network or community. It’s the feeling of not fitting in or not having friends to spend time with. You might have one confidant (so you aren’t emotionally lonely per se), but still feel lonely because you have no group or sense of belonging. Social loneliness often manifests as feeling like an outsider or perceiving that you have fewer friends than others, leading you to withdraw further12. Finally, existential loneliness is a more profound sense of isolation related to meaning and identity. It’s the feeling that “I am alone in the universe” or lacking a sense of purpose or connection to something larger than oneself13. Someone with existential loneliness might have friends and family yet still feel a void a lack of meaning or spiritual connection. This is sometimes called spiritual loneliness or existential angst. In truth, these three types often overlap. A person going through a divorce might experience all three at once: the emotional loss of a partner, the social disruption of shared friend circles, and a crisis of identity and meaning.

Understanding these nuances is important because it reminds us that loneliness is multifaceted. As one scholarly review summarized: “Loneliness means one is not embedded in a personal network, misses closeness and intimacy, and lacks meaning in life.”14In other words, loneliness can come from one or any combination of: not having enough people around, not having enough connection with those around, or not feeling anchored in something that gives life meaning. Throughout different life stages, different facets of loneliness may dominate a teenager might feel more social loneliness (yearning for friendship and acceptance), whereas an older adult might feel more existential loneliness (struggling with purpose after retirement), for example.

Loneliness doesn’t discriminate. It affects people in every culture, across all ages and backgrounds. However, culture does influence how we experience and respond to loneliness. In more individualistic societies (like much of Western Europe or the US), people often live apart from extended family, lead independent lives, and may openly acknowledge feeling lonely. In these societies, social isolation (living alone, etc.) is more common, which can increase loneliness risk1516. In contrast, in more collectivist cultures (like many Arab, African, and Asian societies), individuals are usually surrounded by family or community. One might assume this means they never feel lonely but that’s a myth. Studies find little difference, or even higher reported loneliness in some collectivist cultures15. How can that be? In collectivist settings, people might be less used to solitude, so when they do find themselves alone (even temporarily), it can feel more daunting17. There may also be strict social norms about how one should live for instance, an expectation to marry by a certain age, or to conform to community roles. If someone feels “different” or doesn’t fit those norms, they might experience intense loneliness even while embedded in family or group life1819. For example, a single woman in her late 30s in a society where most her age are married with children might feel acutely lonely and stigmatized for not “fitting in,” even as relatives surround her. Or a young man working abroad to support his family back home may feel profound loneliness (and pressure) despite coming from a culture that values togetherness. In collectivist cultures, people also might stay in unfulfilling relationships because of social pressures; being “trapped” in a marriage or family situation lacking emotional support can breed a deep loneliness that is hard to talk about20. On the flip side, individualistic cultures’ emphasis on personal freedom means people can leave bad relationships or seek new social groups, but it also means they bear sole responsibility for their social life, which can be hard if one is shy or struggling. The bottom line is that no culture has a monopoly on loneliness. We are all human, and humans everywhere need to feel connected and valued. If those needs aren’t met, loneliness results, whether one is in a Manhattan apartment or a village in the Sahara.

Why does loneliness hurt so much? From an evolutionary perspective, our brains are wired to need social connection. Psychologists like John Cacioppo have described loneliness as an alarm signal much like hunger or thirst that evolved to alert us that we are drifting too far from the safety of our social group21. For our distant ancestors, being isolated could mean danger (predators, lack of help, etc.), so those who stayed connected survived. Thus, when we feel lonely, it’s our body-mind’s way of saying “Attend to your relationships!”. Chronic loneliness triggers the body’s stress response. It elevates cortisol (a stress hormone), increases inflammation, and can even suppress immune function. Over time, these physiological effects take a toll, which is why persistent loneliness is linked to a host of health problems: depression, anxiety, poor sleep, high blood pressure, heart disease, a weakened immune system, and cognitive decline, to name a few221. One famous meta-analysis even found that lacking social connection can increase risk of early death by 26%, comparable to the risk from smoking 15 cigarettes a day2. Other studies have found similar risks, showing that loneliness and social isolation can be more dangerous than obesity or lack of exercise2. When public health experts talk about a “loneliness epidemic,” they are highlighting these very real, measurable impacts on our well-being.

Yet, as much as loneliness can harm us, it also motivates us to seek change. We feel lonely because we are meant to seek togetherness. This leads to an important theme you’ll encounter in this book: the double-edged nature of loneliness. In the short run, loneliness is painfulemotionally painful in a way neuroscientists say activates some of the same brain areas as physical pain. But in the long run, that pain can prompt us to take action, to reach out to others or to realign our lives with what matters. In the chapters ahead, we will see how loneliness, when approached with understanding, can catalyze personal growth. For instance, periods of solitude have inspired artists, writers, and thinkers throughout history to create profound works. Modern research likewise shows that if we learn to view solitude in a positive light, it can become a source of creativity, self-discovery, and even contentment, rather than just emptiness2324. A recent global study found that people who reframed time alone as a chosen solitude actually felt more positive and less lonely during alone time, whereas those who believed being alone is terrible felt lonelier and worse2523. In other words, mindset matters. When we interpret loneliness solely as a curse, we may become ashamed of it or fearful, which can trap us in it. But if we accept loneliness as a human signal“I’m thirsty for connection”we can address that need without self-blame.

This book aims to strike a balance: to validate the pain loneliness causes (you’ll see you’re truly not alone in how you feel) and to highlight paths toward hope and meaning (loneliness doesn’t have to be a life sentence).