# Development and cross‐cultural validation of the Japanese version of the Adjustment Disorder‐New Module‐20

## TL;DR

This study developed and validated a Japanese version of the ADNM-20, a tool for assessing adjustment disorder symptoms in the general population.

## Contribution

The paper introduces a culturally adapted and validated Japanese version of the ADNM-20 for assessing adjustment disorder.

## Key findings

- Confirmatory factor analysis supported the six-factor model of the Japanese ADNM-20 with good fit indices.
- The Japanese ADNM-20 showed strong correlations with external measures of depression and anxiety.
- The scale demonstrated excellent internal consistency with a Cronbach's α of 0.953.

## Abstract

Adjustment disorder (AjD) is a prevalent mental disorder with evolving definitions in the International Classification of Diseases, 11th Revision (ICD‐11). The Adjustment Disorder‐New Module‐20 (ADNM‐20) assesses six AjD symptom clusters based on the ICD‐11 criteria and has demonstrated strong psychometric validity. This study aimed to develop and validate a Japanese version of the ADNM‐20 in the general population.

A forward–backward translation approach was used to develop the Japanese version of the ADNM‐20. Psychometric properties were assessed through a web‐based survey of 1314 participants, examining factorial validity, construct validity, and internal consistency.

Confirmatory factor analysis supported the theoretical six‐factor model (comparative fit index = 0.923, root‐mean‐square error of approximation = 0.079), with strong correlations between the ADNM‐20 subscales and external measures (e.g., depression PHQ‐9, r = 0.71; anxiety GAD‐7, r = 0.72). The total ADNM‐20 showed excellent internal consistency (Cronbach's α = 0.953).

The Japanese ADNM‐20 is a valid and reliable scale for assessing AjD symptoms in the Japanese general population. Further studies involving clinical populations are warranted to confirm its applicability in clinical settings.

The Japanese version of the Adjustment Disorder‐New Module‐20 (ADNM‐20) is a valid and reliable instrument for assessing adjustment disorder (AjD) symptoms in the Japanese general population.