Cross-cultural equivalence of the Kessler Psychological Distress Scale (K10) across four African countries in a multi-national study of adults

The Kessler Psychological Distress Scale (K10) has been widely used to screen psychological distress across many countries. However, its performance has not been extensively studied in Africa. The present study sought to evaluate and compare measurement properties of the K10 across four African countries: Ethiopia, Kenya, Uganda, and South Africa. Our hypothesis is that the measure will show equivalence across all. Data are drawn from a neuropsychiatric genetic study among adult participants (<i>N</i> = 9179) from general medical settings in Ethiopia (<i>n</i> = 1928), Kenya (<i>n</i> = 2556), Uganda (<i>n</i> = 2104), and South Africa (<i>n</i> = 2591). A unidimensional model with correlated errors was tested for equivalence across study countries using confirmatory factor analyses and the alignment optimization method. Results displayed 30 % noninvariance (i.e., variation) for both intercepts and factor loadings across all countries. Monte Carlo simulations showed a correlation of 0.998, a good replication of population values, indicating minimal noninvariance, or variation. Items "so nervous," "lack of energy/effortful tasks," and "tired" were consistently equivalent for intercepts and factor loadings, respectively. However, items "depressed" and "so depressed" consistently differed across study countries (R² = 0) for intercepts and factor loadings for both items. The K10 scale likely functions equivalently across the four countries for most items, except "depressed" and "so depressed." Differences in K10 items were more common in Kenya and Ethiopia, suggesting cultural context may influence the interpretation of some items and the potential need for cultural adaptations in these countries.