Cross-cultural comparison of American and Japanese clinical ratings of patients with Major Depressive Disorder using the Hamilton Depression Scale - 17 (HAM-D 17)

Background Where clinical trials are conducted interna-tionally, it is imperative to attend to cultural influences on clinical assessment tools. Cross-cultural literature has consistently shown that the expression of distress differs across cultures (Kirmayer, 2001). In a study looking at dif-ferences in HAM-D scores in Japan, United States, and Europe, Ohishi & Kamijima (2002) indicated that the items depressed mood and „feelings of guilt were rated as less severe in the Japanese cohort. This suggests that ex-pressed emotionality may be assessed differently across cultures and in this study we sought to further explore this dimension. 

Methods We examined the results from 54 American and 106 Japanese raters in a global trial for an antidepressant in development. For training, raters watched and rated two videos of HAM-D interviews conducted in English, each with a depressed woman of Asian descent (Japanese subtitles were provided). The first video depicted a more severely depressed patient (Video 1); the second video was conducted with a moderately depressed patient (Video 2). 

Results In Video 1 we found no significant difference in the overall HAM-D score between Japanese (M=22.88, SD =3.26) and American raters (M= 23.35, SD=3.17), t(133) = 0.816, p =.0416 (two-tailed). However, in Video 2, we found a significant difference in the overall HAM-D scores for Japanese raters (M=17.17, SD=3.08) and American raters (M=18.13, SD=2.35), t(154) = 2.00, p < 0.05, though the magnitude of the differences in the means was small (n2= .025). On Insomnia-Late, Anxiety psychic, and Insight items, Japanese clinicians rated both patients as more severe than American raters. 

Conclusions Our analyses suggest that there are differ-ences in how American and Japanese raters evaluate symptom severities of identical patients. While American and Japanese raters may not rate severely depressed pa-tients (Video 1) that differently from each other, there seem to be cultural influences on how they rate patients with moderate depression (Video 2). The assessment of severe symptomatology does not seem to be impacted by cultural differences. However, rating mild to moderate level of depression may pose more of a challenge and has implications for training as well as interpretation of results from trials conducted in these regions.