such as Claude S. Fischer and Eric Klinenberg opined in 2018 that while the data doesn't support describing loneliness as an "epidemic" or even as a clearly growing problem, loneliness is indeed a serious issue, having a severe health impact on millions of people. However, a 2021 study found that adolescent loneliness in contemporary schools and depression increased substantially and consistently worldwide after 2012. A comparative overview of the prevalence and determinants of loneliness and social isolation in Europe in the pre-COVID period was conducted by Joint Research Centre of the European Commission within the project Loneliness in Europe. The empirical results indicate that 8.6% of the adult population in Europe experience frequent loneliness and 20.8% experience social isolation, with eastern Europe recording the highest prevalence of both phenomena. Effects Transient While unpleasant, temporary feelings of loneliness are sometimes experienced by almost everyone, they are not thought to cause long term harm. Early 20th century work sometimes treated loneliness as a wholly negative phenomena. Yet transient loneliness is now generally considered beneficial. The capacity to feel it may have been evolutionarily selected for, a healthy aversive emotion that motivates individuals to strengthen social connections. Transient loneliness is sometimes compared to short-term hunger, which is unpleasant but ultimately useful as it motivates us to eat. Chronic Long-term loneliness is widely considered a close to entirely harmful condition. Whereas transient loneliness typically motivates us to improve relationships with others, chronic loneliness can have the opposite effect. This is as long-term social isolation can cause hypervigilance. While enhanced vigilance may have been evolutionary adaptive for individuals who went long periods without others watching their backs, it can lead to excessive cynicism and suspicion of other people, which in turn can be detrimental to interpersonal relationships. So without intervention, chronic loneliness can be self-reinforcing. Benefits Much has been written about the benefits of being alone, yet often, even when authors use the word "loneliness", they are referring to what could be more precisely described as voluntary solitude. Yet some assert that even long-term involuntary loneliness can have beneficial effects. Chronic loneliness is often seen as a purely negative phenomena from the lens of social and medical science. Yet in spiritual and artistic traditions, it has been viewed as having mixed effects. Though even within these traditions, there can be warnings not to intentionally seek out chronic loneliness or other conditionsjust advise that if one