Abstract To estimate the prevalence, severity, and treatment ofDiagnostic and Statistical Manual of Mental Disorders(4th edn; DSM‐IV) mental disorders in community populations in Japan, face‐to‐face household surveys were conducted in four community populations in Japan. A total of 1663 community adults responded (overall response rate, 56%). The DSM‐IV disorders, severity, and treatment were assessed with the World Mental Health version of the World Health Organization (WHO) Composite International Diagnostic Interview (WMH‐CIDI), a fully structured lay‐administered psychiatric diagnostic interview. The prevalence of any WMH‐CIDI/DSM‐IV disorder in the prior year was 8.8%, of which 17% of cases were severe and 47% were moderate. Among specific disorders, major depression (2.9%), specific phobia (2.7%), and alcohol abuse/dependence (2.0%) were the most prevalent. Although disorder severity was correlated with probability of treatment, only 19% of the serious or moderate cases received medical treatment in the 12 months before the interview. Older and not currently married individuals had a greater risk of having more severe DSM‐IV disorders if they had experienced any within the previous 12 months. Those who had completed high school or some college were more likely to seek medical treatment than those who had completed college. The study confirmed that the prevalence of DSM‐IV mental disorders was equal to that observed in Asian countries but lower than that in Western countries. The percentage of those receiving medical treatment was low even for those who suffered severe or moderate disorders. Possible strategies are discussed.

Objectives The study investigated the links between workplace measures implemented in response to COVID‐19 with mental health and work performance of employees in Japan. Methods This was a cross‐sectional study of a sample from a cohort study of full‐time employees. Participants (n = 1448) completed an online self‐report questionnaire on March 19‐22, 2020. Multiple linear regression was conducted to ascertain their fear of and worry associated with COVID‐19, psychological distress, and work performance. Results The number of workplace measures correlated positively with respondents' fear of and worry associated with COVID‐19 (adjusted standardized β = 0.123, P < .001), negatively with psychological distress and positively with work performance (adjusted standardized β = −0.068, P = .032; adjusted standardized β = 0.101, P = .002; respectively). Conclusions Workplace measures may promote and maintain the mental health and work performance of employees during the COVID‐19 epidemic. The positive association between the number of measures and fear and worry about COVID‐19 may reflect increased awareness about COVID‐19 among employees resulted from taking the measures.