Aim: Self-reported scales that adequately measure tonic irritability and provide international comparability are lacking in Japan. Therefore, the present study aimed to examine the reliability, validity, and cross-cultural adaptation of both self- and parent-reported versions of the Japanese version of the Affective Reactivity Index.
Methods: We used 2019 data from the Hirosaki City School Cohort Study, which is a part of the Assessment of Preschool to Adolescence-Longitudinal Epidemiological Study. To evaluate the construct validity of the Affective Reactivity Index, we examined the association between depressive symptoms and emotional and conduct problems. We applied item response theory to evaluate the psychometric properties of the Affective Reactivity Index and assess various latent traits.
Results: Our findings confirmed the reliability and construct validity of both the self- and parent-reported versions of the Affective Reactivity Index (α = 0.86 and 0.82, respectively). The item response theory analysis confirmed the psychometric properties of these measures in a Japanese context.
Conclusion: This study comprehensively examined the reliability, validity, and cross-cultural adaptation of the Japanese version of the Affective Reactivity Index for both self- and parent-reports. These findings mark a crucial step in developing culturally adapted tools for assessing irritability in Japanese adolescents, contributing to both research and clinical settings.
Keywords: Affective Reactivity Index; adolescent; cross‐cultural adaptation; irritability; psychometric properties.
© 2025 The Author(s). Psychiatry and Clinical Neurosciences Reports published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Psychiatry and Neurology.