Toward Establishing the Transcultural Validity of Sluggish Cognitive Tempo: Evidence From a Sample of South Korean Children.

All sluggish cognitive tempo (SCT) research has been conducted in North America and Western Europe, with the addition of 1 study in Chile. Our objective was to determine the internal and external validity of 9 SCT and 9 Diagnostic and Statistical Manual of Mental Disorders (5th ed.) attention deficit/hyperactivity disorder inattention (ADHD-IN) symptoms in South Korean children. Mothers, fathers, and teachers rated SCT, ADHD-IN, ADHD hyperactivity/impulsivity (HI), oppositional defiant disorder (ODD), anxiety, depression, academic impairment, and social impairment in 1st- to 6th-grade children (6-13 years of age) from South Korea (Sample 1: mothers rated 885 children and fathers rated 646 children; 941 unique children, 54% girls; Sample 2: 99 teachers rated 297 children, 44% girls). The SCT and ADHD-IN symptoms showed convergent validity (substantial loadings on their respective factors) and discriminant validity (loadings near zero on the alternative factor) across all three raters. Although ADHD-IN showed a positive relationship with ADHD-HI and ODD even after controlling for SCT across all three raters, SCT was nonsignificantly (mothers and fathers) or negatively (teachers) related to ADHD-HI and ODD after controlling for ADHD-IN. Higher SCT scores predicted higher anxiety, depression, academic impairment (teachers only), and social impairment (teachers only) even after controlling for ADHD-IN, whereas higher ADHD-IN scores predicted higher anxiety (mothers and fathers only), depression, academic impairment, and social impairment after controlling for SCT. The study provides initial evidence for the internal and external validity of SCT relative to ADHD-IN in South Korean children, thereby providing the first evidence for SCT's validity in Asian children.