... Interventional studies (Table 1) identified a range of interventions and designs, with variable timing of the interventions, some being once per week for 2 to 4 weeks (Ahmed and Masoom, 2021;Berger et al., 2019), others on a weekly basis of up to 10 weeks (for example, Taylor et al., 2017), and others less intensive but delivered over a year (for example, Stegen and Wankier 2018). Interventions were broadly-collated across different approaches as: diarising/journalling elements (Berger et al., 2019;Chan, 2010;Cheng et al., 2015;Ducasse et al., 2019;Jackowska et al., 2016;Kerr et al., 2015;Killen and Macaskill, 2015;Kini et al., 2016;Krejtz et al., 2016;Mȃirean et al., 2019;Martin et al., 2019;O'Connell et al., 2017;Wolfe and Patterson, 2017); facilitated face-to-face or workshop style interventions delivered as individual or group sessions (Gabana et al., 2019;Martin et al., 2019;Ramírez et al., 2014;Salces-Cubero et al., 2019;Taylor et al., 2017;Yang et al., 2018); gratitude exercises, such as blessings counting, gratitude letters, gratitude lists, and gratitude sharing or expression (Berger et al., 2019;Chan, 2010;Deng et al., 2019;Jackowska et al., 2016;Killen and Macaskill, 2015;Kini et al., 2016;Krejtz et al., 2016;Mȃirean et al., 2019;Otto et al., 2016;Rash et al., 2011;Stegen and Wankier, 2018;Taylor et al., 2017;Wolfe and Patterson, 2017;Yang et al., 2018); a gratitude meditation or contemplation programme (Ahmed and Masoom, 2021); and finally, a number of combined or complex interventions (Berger et al., 2019;Martin et al., 2019;Osborn et al., 2020;Ramírez et al., 2014;Stegen and Wankier, 2018). ...