Supplementary materials EJPA: Validation of the Parent-Report and Self-Report Versions of Highly Sensitive Child Scale in Serbian Samples

The parent-report and self-report forms of the Highly Sensitive Child scale are significant tools for examining environmental sensitivity in children and adolescents. Nevertheless, due to their relatively recent development, these scales have not undergone validation in numerous cultural contexts, and there remains a paucity of studies concerning their psychometric characteristics. A total of 793 parents, and their 793 children from Serbia participated in two studies. Study 1 aimed to assess the structural validity and reliability of the Highly Sensitive Child scale parent-report (HSC-PR), while Study 2 aimed to investigate the factor structure, measurement invariance, and convergent validity of the Highly Sensitive Child scale self-report (HSC-SR) version. The results supported the HSC-PR and HSC-SR three-factor structure as well as scalar measurement invariance across gender. Hence, correlations with convergent measures (positive affect, negative affect, and physiological hyperarousal) indicate that there are three distinct dimensions contributing to children's well-being in different ways. Additionally, the subscale of high sensitivity that appears to have a negative impact on children’s well-being is Ease of Excitation. The reliability of responses obtained from two different assessment agents will also be discussed.