Association of response rate and prevalence estimates of common mental disorders across 129 areas in a nationally representative survey of adults in Japan

Objective To investigate the association of area response rate with prevalence estimates of mental disorders in the 2nd World Mental Health Survey (WMHJ2). Methods The sample of the WMHJ2 was selected from community residents in 129 areas from three regions of Japan. The surveys were conducted between 2013 and 2015, and 2450 (43.4%) responded. Mental disorders as well as three disorder classes (mood, anxiety, and substance use disorders) were identified using the WHO CIDI/DSM-IV. Response rates and 12-month and lifetime prevalences were calculated for each area. A generalized linear mixed model analysis was conducted to associate area response rate with the prevalence of mental disorders, controlling for sex, age, urbanity, and geographical region. Results Area response rates ranged from 0.05 to 0.80 across the 129 areas. Area response rate was not significantly associated with 12-month or lifetime prevalence of mental disorder. Lifetime prevalences of substance use disorder were significantly lower in a survey with a higher response rate than a survey of the same area with a lower response rate. Conclusion Response rate may not strongly affect the prevalence estimates of mental disorders in a community-based survey of the prevalence of common mental disorders during a particular time frame. However, a lower response rate could be associated with overestimation of lifetime prevalence of substance use disorder. This needs further elucidation.