A cross-cultural comparison study of depression assessments conducted in Japan

BACKGROUND: The advent of global clinical trials has necessitated the use of English-based rating instruments in diverse cultures where English is clearly not the primary language. The cross-cultural applicability of rating instruments developed in one language with only one cultural group is an important issue in both research and clinical settings where these instruments might be used. We examined the cross-cultural applicability of the Montgomery-Asberg Depression Rating Scale (MADRS) in Japan. METHODS: As part of a rater-training program for a clinical trial in Japan, we assessed inter-rater agreement using two videotaped MADRS interviews administered in Japanese and produced with English subtitles. We looked for possible interpretational variance that might have been generated by cultural differences between Japanese raters in Japan and English-speaking raters in the USA scoring the same interviews. RESULTS: The US and Japanese raters demonstrated high inter-rater agreement and no significant scoring difference on the total MADRS score. The subtitles in English did not adversely affect the overall scoring. We separately analyzed the 10 individual items from each of the two MADRS interviews used for rater training. Of the 20 items, 18 were concordant between the US and Japanese raters. In one interview, the US raters scored lassitude significantly higher (p = 0.013) and the inability to feel significantly lower (p = 0.037) than the Japanese raters, reflecting a possible interpretational difference on these items. CONCLUSION: Although developed in Europe, these findings support the general applicability of the MADRS to assess the severity of depressive symptoms in Japan. We did note significant scoring differences on 2 of the 20 individual items, suggesting a possible cultural difference. It is possible that more interviews might have revealed more interpretational differences. These findings highlight the need for cultural familiarity when assessing psychiatric patients.