Validity and reliability of the Japanese version of the Child and Adolescent Behavior Inventory: Parent version.

We developed a Japanese version of the Child and Adolescent Behavior Inventory (CABI) and evaluated its validity and reliability. A total of 2433 parents and 108 students in grades 4 and above participated in this study. First, we assessed the agreement between the parents' evaluations of internalizing disorders (anxiety and depression modules) and their children's self-reports. The criterion-related validity of attention deficit hyperactivity disorder (ADHD)-inattention, ADHD-hyperactivity/impulsivity, and oppositional defiant disorder (ODD) modules was also evaluated. Subsequently, we investigated whether cognitive disengagement syndrome (CDS) items differed from the ADHD items through factor analysis and examined the relationship between CDS and internalizing problems. Finally, we established normative data to adapt the CABI for use in the Japanese population. Parents' observational evaluations of internalizing disorders showed moderate agreement with children's self-reports. The ADHD-inattention, ADHD-hyperactivity/impulsivity, and ODD modules demonstrated moderate to high criterion-related validity. Factor analysis revealed that the CDS module assesses symptoms distinct from ADHD symptoms. In the Japanese population, CDS exhibited a two-factor structure (daydreaming and mental confusion), with developmental changes observed across age groups. The internal consistency and test-retest reliability of the CABI are moderate to high. The scores of each CABI module were found to be reliable and valid within the Japanese sample. Future clinical research should focus on the evaluation of CDS, which is often comorbid with ADHD.