The World Mental Health Survey Japan was conducted to address the current status of mental disorders in Japan. Among the various regions covered by the survey were Tendo City and Kaminoyama City in Yamagata Prefecture. The suicide and alcohol consumption rates in Yamagata are higher than the Japanese national average. Many studies have reported that major depressive disorder (MDD), alcohol use disorders (AUDs), and suicidal ideation are related to suicide risk. The prevalence of MDD, AUDs, and suicidal ideation, as well as the association between suicidal ideation and mental disorders must be investigated in order to implement mental health and suicide prevention measures in our community; however, only a few studies have addressed this issue.

The survey involved face-to-face interviews. The study population consisted of 1,684 adult residents, of which 770 (mean age 54.0 ± 17.4 years) who completed the interview process. Mental disorders were assessed using the World Mental Health version of the World Health Organization Composite International Diagnostic Interview .

Among the study population, lifetime prevalence of MDD was 4.4%, which was similar to values reported in previous studies in Japan. Prevalence of AUDs, however, was 10.2%, which was higher those reported previously. We observed a significant association between suicidal ideation and MDD [odds ratio (OR) 7.6], our results showed precisely the opposite association between AUDs and suicidal ideation (OR 0.5, not significant) compared to previous studies.

Although prevalences of MDD and suicidal ideation were not high, this study revealed a high lifetime prevalence of AUDs and a negative association between suicidal ideation and AUDs.