Loneliness has evolved to help us survive, just like hunger, thirst, and physical pain. Loneliness motivates the renewal of social connections, just like hunger movitates us to eat, thirst movitates us to drink, and physical pain motivates us to avoid and treat the source of the pain. The renewal of quality social connections enabled us to belong to groups that provided mutual protection and assistance, so to help our species survive in the past. Feeling lonely activates neurobiological mechanisms that in the short term may promote self-preservation but in the long term may be deterimental to health and well-being (Cacioppo and Cacioppo 2014). Loneliness – if not addressed – can have serious cumulative long-term health effects.
Researchers have found that the fully adjusted effects of loneliness give rise to a 26% increase in the likelihood of premature mortality (Holt-Lunstad et al 2015). This has a parallel to the findings last century that there was a higher mortality rate for children in orphanages with little personal contact (Holt-Lunstad et al 2010).
Given the impact of loneliness is comparable to other well-established mortality risk factors (e.g. physical inactivity, obesity, lack of immunization, and non-access to health care), “it seems prudent to add social isolation and loneliness to lists of public health concerns” (Holt-Lunstad et al 2015).
The health effects of loneliness may be classified into mental health effects and physical health effects. In addition, there are other lifestyle factors that are frequently associated with loneliness. These associated lifestyle factors are not necessarily the cause of loneliness, but rather may occur in parallel (e.g. due to a common cause).
In addition to the effects, there are life-style associations related to loneliness. We have to be careful when interpreting these factors: loneliness could cause these factors, these factors could cause loneliness, or both could be related to a common cause.
Research has found that those who are lonely are 40% more likely to be diabetic, 13% more likely to smoke, 20% more likely to be less physically active, and 31% more likely to have high cholesterol (Richard et al 2017). Loneliness has also been associated with sleep dysfunction (Cacioppo et al 2002).
John Cacioppo and Stephanie Cacioppo (2014), “Social relationships and health: The toxic effects of perceived social isolation”, Social and personality psychology compass, vol. 8(2), p. 58–72. Read the article.
Julianne Holt-Lunstad, Timothy Smith, and J. J. Bradley Layton (2010), “Social relationships and mortality risk: A meta-analytic review”, PLoS Medicine, vol. 7(7), e1000316. Read the article.
Julianne Holt-Lunstad, Timothy Smith, Mark Baker, Tyler Harris, and David Stephenson (2015), “Loneliness and social isolation as risk factors for mortality: A meta-analytic review”, Perspectives on psychological science, vol. 10(2), p. 227–237. Read the article.
Aline Richard, Sabine Rohrmann, Caroline Vandeleur, Margareta Schmid, Jurgen Bart, and Monika Eichholzer (2017), “Loneliness is adversely associated with physical and mental health and lifestyle factors: Results from a Swiss national survey”, PLoS ONE, vol. 12(7), e0181442. Read the article.
John Cacioppo, Louise Hawkley, L. Crawford, J. Ernst, M. Burleson, R. Kowalewski, W. Malarkey, E. Van Cauter, and G. Berntson (2002), “Loneliness and health: potential mechanisms”, Psychomatic medicine, vol. 64(3), p. 407-417. Read the abstract.