Research paper · RP40

Adapted Beats Imported

Hendriks and colleagues reported that positive-psychology interventions (PPIs) run outside the West produced a moderate effect on subjective wellbeing (Hedges g = 0.48). No trial directly compared an adapted PPI with an unadapted version of the same programme in a South Asian adult sample, so a pooled estimate of the adaptation increment is not possible. This PRISMA-2020 systematic review asked how much cultural adaptation adds to PPI effects on wellbeing and depressive symptoms among South Asian adults (India, Pakistan, Bangladesh, Sri Lanka, Nepal, and diaspora), 2005–2026. Databases and registries searched were PubMed, PsycINFO, Scopus, Web of Science, Google Scholar, CTRI, ClinicalTrials.gov and OSF. Eligible designs were randomised and controlled trials of gratitude, strengths, savouring or multi-component PPI practices versus control or versus an unadapted version. Zero trials isolated the adaptation increment. Nine adult PPI-versus-control studies entered a narrative synthesis (India seven, Pakistan two, Bangladesh zero, Sri Lanka zero core PPI, Nepal zero, diaspora zero). Locally built strengths programmes produced small-to-moderate wellbeing gains against waitlist or usual supervision: the only fully reported between-arm standardised difference was Bondre 2025, Cohen’s d = 0.55 (95% CI 0.04 to 1.06) for happiness in rural Indian women health workers. Imported gratitude scripts often failed to raise state gratitude in Indian adults. A 2025 cross-cultural meta-analysis found no significant gratitude effect on wellbeing in India. Study quality was low. Certainty for the adaptation-increment question is very low because the comparison does not yet exist. The practical implication is not “PPIs do not work in South Asia.” It is that a worksheet trained on California undergraduates is a poorly specified model for a Mumbai working week. Domain shift is not a slogan. It is the finding.