Abstract

This study aimed to adapt and validate the Mental Health Support Scale (MHSS) for Chile and Argentina, hypothesising that it would correlate positively with mental health literacy, negatively with stigma measures, and differ by mental health first aid (MHFA) training history. The MHSS involves the ‘Intended’ scale (assessing intended support) and the ‘Provided’ scale (evaluating actual help), capturing recommended and not-recommended actions. The scales were translated into Spanish, piloted with 17 adults to explore cultural relevance, and validated with 554 Chilean and Argentinian adults using concurrent measures of stigma, social distance and mental health literacy. Factor analysis of the MHSS-Intended identified a recommended factor (16 items) and a not-recommended factor (5 items). The recommended factor correlated positively with mental health literacy (r = 0.19) and negatively with weak-not-sick stigma (r = -0.16) and social distance (r = -0.16). Support scores significantly discriminated between participants with and without MHFA training (recommended d = 0.99, not-recommended d = 1.35) and within participants pre- and post-MHFA training (recommended d = 0.90, not recommend d = 0.47). Overall, the adapted MHSS demonstrates acceptable psychometric properties and is a promising tool for evaluating mental health first aid support in Chile and Argentina. © The Author(s), 2025. Published by Cambridge University Press.