Impact of mental disorders on work performance in a community sample of workers in Japan: the World Mental Health Japan Survey 2002-2005.

Most studies that investigate the impact of mental disorders on work performance have been conducted in Western countries, but this study examines the impact of common mental disorders on sick leave and on-the-job work performance in a community sample of Japanese workers. Data from the World Mental Health Japan survey were analyzed. A subsample of 530 workers aged 20-60years were interviewed using the WHO Composite International Diagnostic Interview 3.0. The WHO Health and Work Performance Questionnaire, was used to assess sick days and on-the-job work performance for the previous 30days. Linear regression was used to estimate the impact of mental disorders on these indicators of work performance over 12months. Mood disorders, including major depressive disorder, and alcohol abuse/dependence were significantly associated with decreased on-the-job performance. There were no significant associations between mental disorders and sick/absent days. Consistent with previous studies, major depression has a great impact on on-the-job work performance in Japan. The lost productivity was estimated at approximately 28-30 lost days per year. A similar decrease in on-the-job work performance was found for alcohol abuse/dependence, which is stronger than that in other countries, probably attributable to greater tolerance of problematic drinking at Japanese worksites.

Cost of depression among adults in Japan in 2005.

AIM: Major depression is expected to become the leading contributor to disease burden worldwide by 2020. Previous studies have shown that the societal cost of depression is not less than that of other major illnesses, such as cardiovascular diseases or AIDS. Nevertheless, the cost of depression in Japan has never been examined. The goal of the present study was to estimate the total cost of depression in Japan and to clarify the characteristics of this burden. METHODS: A prevalence-based approach was adopted to measure the total cost of depression. The total cost of depression was regarded as being comprised of the direct cost, morbidity cost and mortality cost. Diagnoses included in this study were depressive episodes and recurrent depressive disorder according to the ICD-10 or major depressive disorder according to the DSM-IV. Data were collected from publicly available statistics and the World Mental Health Japan Survey database. RESULTS: The total cost of depression among adults in Japan in 2005 was estimated to be ¥2.0 trillion. The direct cost was ¥0.18 trillion. The morbidity cost was ¥0.92 trillion, while the mortality cost was ¥0.88 trillion. CONCLUSION: The societal costs caused by depression in Japan are enormous, as in other developed countries. Low morbidity costs and extremely high mortality costs are characteristic in Japan. Effective interventions for preventing suicide could reduce the societal costs of depression.