Age differences among Japanese on the Center for Epidemiologic Studies Depression Scale: an ethnocultural perspective on somatization.

The Japanese version of the Center for Epidemiologic Studies Depression Scale (CES-D) was subjected to principal component (PC) analysis with oblique rotation, as well as an examination of internal consistency, using data obtained from 2,016 adult employees aged 19-63 years. Analyses focused on age differences in these psychometric properties of the CES-D. Coefficient-alpha was sufficiently high for all age groups but was lower than reported in U.S. studies. Positive affect items lowered internal consistency. The PC analyses extracted four factors for each age group. Depressive affect items did not group into one factor; some were combined with somatic or interpersonal items, and the remainder constituted the smallest factor. These three main factors, 'somatic+depressed', interpersonal + negative' and 'positive affect' were comparable across age groups except for those aged 50-63 years. For those aged 50-63 years, the first two factors were combined into a large 'general dysphoria' factor, suggesting a more unified conceptualization of depressive mood. Although 'positive affect' was stable cross-culturally, it was not related to depressive symptomatology as measured by the other items, for Japanese. The 'interpersonal + negative' appears unique for Japanese, indicating the association of interpersonal relations with depressive mood in Japanese. The effects of age-specific ethnocultural factors in Japan on depressive symptomatology are discussed.