... A breakdown of age categories was performed for later sensitivity analysis. The categorization was based on theoretical considerations regarding major developmental stages, namely Erikson's (1950) psychosocial development theory and Arnett's (2015) theory of emerging adulthood, and alignment with related research (Luhmann & Hawkley, 2016, Rokach, 2000, Victor & Yang, 2012, Yang & Victor, 2011. Five studies included only children (0-15 years; Berguno et al., 2004, Karnick, 2008, Kirova-Petrova, 2000, Kristensen, 1995, Martin et al., 2014, two studies included only young adults (16-29 years;Firmin et al., 2014, Rönkä et al., 2018, and eleven studies included only older adults (60 years and older; Graneheim & Lundman, 2010, Heravi-Karimooi et al., 2010, Kwegyir Tsiboe, 2021, McInnis & White, 2001, Morgan & Burholt, 2020, Ojembe & Ebe Kalu, 2018, Park et al., 2019, Smith, 2012, Sullivan et al., 2016, Tiilikainen & Seppänen, 2017, Wright-St Clair & Nayar, 2020. ...