Long-Term Effects of a Screening Intervention for Depression on Suicide Rates among Japanese Community-Dwelling Older Adults

Abstract

To explore the long-term impact of a universal screening intervention for depression on suicide rates among older community-dwelling adults, with gender as an effect modifier. Controlled cohort study reporting long-term follow-up of previous research. Two sets of three municipalities in Japan were assigned as intervention and control regions and compared with the surrounding zone and prefecture. Intervention area residents aged 60 years and older (14,291) were invited to participate in a 2-year intervention (2005-2006). Four population-based dynamic cohorts of residents aged 65 years and older (1999-2010) were included as subjects, 6 years before and after the intervention started. At-risk residents within the intervention region (4,918) were invited for a two-step screening program; 2,552 participated in the program linked with care/support services for 2 years. An education program open to the public was held. Changes in suicide from a 6-year baseline to the 2-year intervention and a 4-year follow-up in the intervention region (11,700 adults ≥65 years) were compared with a matched control and two comparison areas using mixed-effects negative binomial regression models. Suicide rates among older adults exposed to screening were compared with those of the control region. Suicide rates in the intervention region decreased by 48%, which was significantly greater than in the three comparison areas. The program's benefits lasted longer for women than men. Screening exposure may be associated with decreased suicide risk over the 4-year follow-up. Universal screening may decrease suicide rates among older adults, with potential gender differences in treatment response.