“…All studies had similar methodological designs (RCT with baseline data). However, the length of follow-up varied from immediately after the intervention (Auyeung & Mo, 2018; Bekhet, 2017; Layous, Nelson, & Lyubomirsky, 2013), to shorter periods of two weeks (Seear & Vella-Brodrick, 2013), and longer periods of 2 months (Sergeant & Mongrain, 2014; Strachan et al, 2017) and 6 months (Gander et al, 2013; Shapira & Mongrain, 2010). Five articles reported convenience sampling, whereas the rest had purposive samples (e.g., students in Hong Kong, caregivers of people with autism).…”