Burenkova, O. V., Dolgorukova, T. A., An, I., Kustova, T. A., Podturkin, A. A., Shurdova, E. M., Talantseva, O. I., Zhukova, M. A., & Grigorenko, E. L. (2023). Endogenous oxytocin and human social interactions: A systematic review and meta-analysis. Psychological Bulletin, 149(9–10), 549–579. https://doi.org/10.1037/bul0000402

Blodgett, J. M., Tiley, K., Harkness, F., & Musella, M. (2025). What works to reduce loneliness: A rapid systematic review of 101 interventions. Journal of Public Health Policy, 46(2), 245–268. https://doi.org/10.1057/s41271-025-00561-1

Cacioppo, J. T., Cacioppo, S., Capitanio, J. P., & Cole, S. W. (2015). The neuroendocrinology of social isolation. Annual Review of Psychology, 66, 733–767. https://doi.org/10.1146/annurev-psych-010814-015240

Delgado, M. R., Fareri, D. S., & Chang, L. J. (2023). Characterizing the mechanisms of social connection. Neuron, 111(24), 3911–3925. https://doi.org/10.1016/j.neuron.2023.09.012

Dunbar, R. I. M., Baron, R., Frangou, A., Pearce, E., van Leeuwen, E. J. C., Stow, J., Partridge, G., MacDonald, I., Barra, V., & van Vugt, M. (2012). Social laughter is correlated with an elevated pain threshold. Proceedings of the Royal Society B: Biological Sciences, 279(1731), 1161–1167. https://doi.org/10.1098/rspb.2011.1373

Fineberg, S. K., & Ross, D. A. (2017). Oxytocin and the social brain. Biological Psychiatry, 81(3), e19–e21. https://doi.org/10.1016/j.biopsych.2016.11.004

Huang, G., Yang, X., Yao, L., Li, X., Wu, Y., Zhou, S., & Wang, Y. (2026). The effectiveness of social support interventions on loneliness among older people in the community: A meta-analysis of randomised controlled trials. Frontiers in Aging, 6, Article 1594513. https://doi.org/10.3389/fragi.2025.1594513

Kim, M. J., & Sul, S. (2023). On the relationship between the social brain, social connectedness, and wellbeing. Frontiers in Psychiatry, 14, Article 1112438. https://doi.org/10.3389/fpsyt.2023.1112438

Lieberz, J., Shamay-Tsoory, S. G., Saporta, N., Esser, T., Kuskova, E., Stoffel-Wagner, B., Hurlemann, R., & Scheele, D. (2021). Loneliness and the social brain: How perceived social isolation impairs human interactions. Advanced Science, 8(21), Article 2102076. https://doi.org/10.1002/advs.202102076

Lasgaard, M., Qualter, P., Løvschall, C., Laustsen, L. M., Lim, M. H., Sjøl, S. E., Burke, L., Blæhr, E. E., Maindal, H. T., Hargaard, A.-S., Christensen, R., & Christiansen, J. (2026). Are loneliness interventions effective for reducing loneliness? A meta-analytic review of 280 studies. American Psychologist, 81(1), 36–52. https://doi.org/10.1037/amp0001578

Masi, C. M., Chen, H.-Y., Hawkley, L. C., & Cacioppo, J. T. (2011). A meta-analysis of interventions to reduce loneliness. Personality and Social Psychology Review, 15(3), 219–266. https://doi.org/10.1177/1088868310377394

McNamara, N., Stevenson, C., Costa, S., Bowe, M., Wakefield, J., Kellezi, B., Wilson, I., Halder, M., & Mair, E. (2021). Community identification, social support, and loneliness: The benefits of social identification for personal well-being. British Journal of Social Psychology, 60(4), 1379–1402. https://doi.org/10.1111/bjso.12456

Batten, S. R., Bang, D., Kopell, B. H., Davis, A. N., Heflin, M., Fu, Q., Perl, O., Ziafat, K., Hashemi, A., Saez, I., Barbosa, L. S., Twomey, T., Lohrenz, T., White, J. P., Dayan, P., Charney, A. W., Figee, M., Mayberg, H. S., Kishida, K. T., Gu, X., & Montague, P. R. (2024). Dopamine and serotonin in human substantia nigra track social context and value signals during economic exchange. Nature Human Behaviour, 8(4), 718–728. https://doi.org/10.1038/s41562-024-01831-w

Office of the Surgeon General [OSG]. (2023). Our epidemic of loneliness and isolation: The U.S. Surgeon General’s advisory on the healing effects of social connection and community. U.S. Department of Health and Human Services. https://www.hhs.gov/sites/default/files/surgeon-general-social-connection-advisory.pdf

Sánchez-Moreno, E., Gallardo-Peralta, L. P., Rodríguez-Rodríguez, V., de Gea Grela, P., & García Aguña, S. (2025). Unravelling the complexity of the relationship between social support sources and loneliness: A mixed-methods study with older adults. PLOS ONE, 20(1), Article e0316751. https://doi.org/10.1371/journal.pone.0316751

Shields, G. S., Spahr, C. M., & Slavich, G. M. (2020). Psychosocial interventions and immune system function: A systematic review and meta-analysis of randomized clinical trials. JAMA Psychiatry, 77(10), 1031–1043. https://doi.org/10.1001/jamapsychiatry.2020.0431

Thompson, A., Smith, M. A., McNeill, A., & Pollet, T. V. (2024). Friendships, loneliness and psychological wellbeing in older adults: A limit to the benefit of the number of friends. Ageing & Society, 44(5), 1090–1115. https://doi.org/10.1017/S0144686X22000666

Tong, X., Yu, L., Wang, Y., Chi, I., & Fu, H. (2021). Systematic review of efficacy of interventions for social isolation of older adults. Frontiers in Psychology, 12, Article 554145. https://doi.org/10.3389/fpsyg.2021.554145

Wickramaratne, P. J., Yangchen, T., Lepow, L., Patra, B. G., Glicksberg, B. S., Talati, A., Adekkanattu, P., Ryu, E., Biernacka, J. M., Charney, A., Mann, J. J., Pathak, J., Olfson, M., & Weissman, M. M. (2022). Social connectedness as a determinant of mental health: A scoping review. PLOS ONE, 17(10), Article e0275004. https://doi.org/10.1371/journal.pone.0275004

Yalom, I. D., & Leszcz, M. (2005). The theory and practice of group psychotherapy (5th ed.). Basic Books.

Zak, P. J. (2012). The moral molecule: The source of love and prosperity. Dutton.