Abstract
Depression and posttraumatic stress disorder (PTSD) represent 2 common mental health sequelae of natural disasters. However, to date, no studies have examined whether postdisaster depression and PTSD are associated with increased risk of mortality among community-dwelling survivors of natural disasters. To assess whether postdisaster depression and PTSD were associated with mortality in older disaster survivors. In this cohort study, prospective data were retrieved from older Japanese adults in Iwanuma City, Miyagi Prefecture, which was directly affected by the 2011 Great East Japan Earthquake and Tsunami. The baseline was established 7 months before the disaster (August 2010), and follow-up surveys were conducted approximately 2.5 years afterward (October 1, 2013, to January 31, 2014). Invitations were mailed to every citizen 65 years or older in Iwanuma City. Mortality data were obtained through March 4, 2017. Data analysis was performed from December 1, 2018, to June 30, 2019. Postdisaster depression (Geriatric Depression Scale Short Form score ≥5) and PTSD (Screening Questionnaire for Disaster Mental Health PTSD subscale score ≥4) were measured in 2013. Mortality data were obtained by linkage to the national long-term care insurance database. Cox proportional hazards regression models were adjusted for predisaster sociodemographic characteristics, health behaviors, social cohesion, predisaster depression, and disaster experiences. The response rate for the baseline survey was 59.0% (5058 of 8567 individuals), and the follow-up rate was 82.1% (3594 of 4380 eligible respondents). A total of 2965 individuals (mean [SD] age, 73.4 [6.2] years; 1621 [54.7%] female) participated in the study. The mean (SD) follow-up since the 2013 survey was 3.3 (0.5) years. Overall, 974 (32.8%) reported postdisaster depression and 747 (25.2%) reported PTSD. In adjusted models, depression was associated with more than double the risk of mortality (hazard ratio, 2.29; 95% CI, 1.54-3.42); PTSD was not associated with increased risk of mortality (hazard ratio, 1.10; 95% CI, 0.73-1.64). When evaluating the association of the 4-category comorbid depression and PTSD variable with mortality, survivors with depression only (HR, 2.24; 95% CI, 1.43-3.49) as well as those with comorbid depression and PTSD (HR, 2.54; 95% CI, 1.50-4.27) were at increased risk of death during the follow-up period compared with those with neither depression nor PTSD. Depression, but not PTSD, was associated with mortality during 3.3 years of follow-up among older disaster survivors. These findings suggest that long-term mental health consequences of natural disasters may exist and that treating depression in older survivors of disasters may be beneficial.
Highlights
Depression and posttraumatic stress disorder (PTSD) are among the most common mental disorders and confer a heavy burden for individuals, the health care system, and society
Depression was associated with more than double the risk of mortality; PTSD was not associated with increased risk of mortality
Depression, but not PTSD, was associated with mortality during 3.3 years of follow-up among older disaster survivors. These findings suggest that long-term mental health consequences of natural disasters may exist and that treating depression in older survivors of disasters may be beneficial
Summary
Depression and posttraumatic stress disorder (PTSD) are among the most common mental disorders and confer a heavy burden for individuals, the health care system, and society. The estimated lifetime prevalence is 16.6% for major depressive disorder and 7.8% for PTSD,[1,2] and depression and PTSD frequently co-occur.[2] In addition to the significant mental health burden, studies[3,4,5,6,7,8,9,10,11,12,13] suggest that depression and PTSD are associated with elevated risk of cardiovascular diseases, diabetes, functional impairment, lower quality of life, and mortality, mostly in patient, veteran, and general population samples. Individuals exposed to natural disasters experience an increased risk of mortality.[14] They experience an increased risk of depression and PTSD. Despite the abundance of literature documenting the prevalence and factors associated with mental health problems after disaster exposure,[16,17,18,19,20,21,22] no studies, to our knowledge, have examined whether depression and PTSD are associated with reduced risk of survival among community-dwelling natural disaster survivors, among older survivors—the population most likely to develop mental health problems after disaster exposure.[23]
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