Objective Adverse life events have been associated with exacerbating multiple sclerosis (MS) symptoms, but results have been variable, raising the question on the role of other psychological factors. This study examined the role of psychological resilience and vulnerability as mediators between adverse life events on MS symptoms. Methods Participants with MS (N = 1239) were aged 18 to 81 years (mean [SD] = 45.6 [10.4] years), and 84.5% were female. MS symptoms were measured by the modified Fatigue Severity Scale, modified Fatigue Assessment Scale, Motor Dysfunction Assessment Scale, Paraesthesiae Spell Duration Scale, and the Paraesthesiae Cumulative Duration Scale. Psychological measures included the Connor-Davidson Resilience Scale, Resilience Scale for Adults, Psychological Vulnerability Scale, the vulnerability section of the Defence Style Questionnaire, and the Adverse Life Events Assessment Scale. Regression analyses and structural equation modeling were performed. Results Adverse life events during the preceding 60 days were associated with fatigue, motor dysfunction, and paresthesia, but with small effect sizes (β from 0.07 to 0.15; p ≤ .014). A structural equation model by which resilience mediated less and vulnerability more MS symptoms after adverse life events during the preceding 60 days showed a statistically significant fit with the data of a moderate to good degree (p < .001; goodness-of-fit statistic = 0.725; root mean square error of approximation = 0.047). Vulnerability played a markedly larger role than did resilience. Conclusion The results suggest that psychological resilience and vulnerability play mediating roles in the relation between adverse life events and MS symptoms, but other psychological factors also need to be investigated.

<p><strong>Background:</strong> The problem of enhancing validity in cross-cultural psychometric-test development in the field of clinical psychology has been perpetuated by several factors. Societal biases and value judgements, a positivistic paradigm, and challenges associated with multiculturalism continually spill over into cross-cultural research methodology. An overemphasis on quantitative methods and insufficient exploration of the meaning of the concepts to be measured tend to threaten construct validity. <strong></strong></p><p><strong>Objectives and Methods:</strong> This article tracks some of the progress in the field of clinical cross-cultural psychometric-test development – prior to and since the International Test Commission Guidelines, and including the complex South African situation – to give support to the perspective that previous cross-cultural research inadequately equips contemporary researchers to develop valid tests for multicultural clinical contexts.</p><p><strong>Results:</strong> A systems-informed paradigm shift is proposed, which involves the application of systemic concepts such as circularity, relationality, neutrality, and a concern with process issues. Ideally, multidisciplinary, multicultural test-developing teams that include members of the target-cultural group should consult and collaborate with the target groups before embarking on test-adaptation or test-development activities. Such teamwork would help to ensure that the meaning of the relevant concept/s is captured in a valid way for each cultural group. Furthermore, such collaboration should form a part of using qualitative research designs more frequently in clinical cross-cultural psychometric-test development.</p><p><strong>Conclusions:</strong> The emphasis should be on building theory and generating hypotheses, in order to pursue a deeper understanding of the constructs under investigation, and to advance theoretical developments in the field of clinical cross-cultural psychometric-test development.</p>