One in six people worldwide is affected by loneliness, which, along with social isolation, can lead to physical illness, contributing to 871,000 deaths worldwide annually, a World Health Organization (WHO) commission has said.
Loneliness increases the risk of strokes, heart attacks, diabetes, depression, anxiety and suicide, the WHO said.
Lonely teenagers are 22% more likely to achieve lower grades than their peers, while lonely adults face greater challenges in finding or keeping a job.
The impact is not only individual but also societal, with billions in costs to health care systems and losses in employment.
The commission's co-chair, Vivek Murthy, defines loneliness as "a painful, subjective feeling that many of us experience when the relationships that we need do not match the relationships that we have. And social isolation, by contrast, is an objective state of having few relationships or interactions."
One in three older people and one in four adolescents are estimated to be socially isolated, according to the report.
Causes include illness, poor education, low income, a lack of opportunities for social interaction, living alone and the use of digital technologies.
Murthy noted that humans have communicated for millennia not only through words but also through facial expressions, body language, tone of voice and silence.
These forms of communication are lost when people rely solely on mobile phones and social media.
The WHO highlighted Sweden as a positive example. The country has implemented a national strategy against loneliness, as reported by Swedish Social Minister Jakob Forssmed.
Sweden recognizes that loneliness is not just an individual problem but one that affects society as a whole. Efforts are being made to foster social connections in places like shops, restaurants, neighbourhoods and clubs.
Soon, all children and teenagers in Sweden will receive prepaid cards that can only be used to book group leisure activities.
Sweden plans to ban mobile phones in public schools, Forssmed said. Studies have shown that this increases social interaction and reduces cyberbullying.
Children and teenagers sleep better and find it easier to put their phones aside during their free time. Forssmed added that children are often frustrated when their parents are constantly distracted by their phones.
While digital technologies have their benefits, such as enabling video calls that were previously impossible, the commission emphasized the importance of creating spaces in life where people can interact face-to-face without technological distractions.
Murthy said "having places and spaces in our life where we can interact face to face with other people without the distraction of technology is very important."
