This study compared representative samples of 2 cross-sectional surveys conducted a decade apart to identify changes in the prevalence and factors associated with depression and suicidal behavior among older adults in Korea. Over 10 years, the prevalence of depression and suicidal behavior showed different patterns. The prevalence of suicidal behavior was slightly lower in 2021 compared to 2011, whereas late-life depression was more prevalent in the recent study. This increased pattern was prominent in men but not in women. The influence of sociodemographic factors on depression and suicidal behavior in older adults also changed from 2011 to 2021. In 2011, being female was the only risk factor for late-life depression. In contrast, several socioeconomic factors were identified as contributing factors in 2021: depression was associated with marital status, low income, and education level. Low-income status also showed a larger impact on suicidal behavior in older adults in 2021 compared to 2011.
We observed a higher prevalence of depression in 2021 study, which was consistent with prior studies both in Korea and global areas[20, 21]. These findings may be explained by changes in the characteristics of older adults in the past decade, such as the inclusion of the baby boomer generation as old adults. The Korean baby boomers are those born between 1955 and 1963, following the Korean War[22]. Although they experienced a period of devastating turmoil after the war, they also experienced a period of economic prosperity with rapid economic growth. Education levels have also increased compared to previous generations[8, 23, 24]. However, all of these changes occurred in such a short period of time that they likely faced many stressful situations. For example, from a social perspective, this generation experienced rapid urbanization, industrialization, and the breakdown of the traditional family system[25]. On an individual level, they had to endure long working hours in a harsh and competitive environment in the name of economic growth. During the economic crisis of the mid-1990s, they also faced a job loss crisis[8, 20, 26].
Baby boomers have had a difficult time continuing to adapt to such rapid social changes and may have been underprepared economically and psychologically for old age. While socioeconomic conditions have changed dramatically in Korea, the old values emphasizing the responsibility of supporting parents and raising children have not changed much[8, 27]. Therefore, baby boomers may not have had the opportunity to prepare for old age, not only because of their own adjustment problems but also because of the responsibility of supporting their families. The combination of unprepared later life and accumulated stress in this generation may contribute to the increase in the prevalence of depression.
This study showed a downward trend in the prevalence of suicidal behaviors among older Korean people, although it was not statistically confirmed. This decreasing pattern has also been reported in other countries[21, 28]. Korean statistics also reported a decline in the suicide rates in older adults from its peak of 81.9 per 100,000 in 2010 to 42.2 per 100,000 in 2020[5]. This decreasing trend in suicide may be attributed to the ongoing suicide prevention efforts in Korea, such as the National Suicide Prevention Initiative in 2009 and the legislation of The Act for Preventing Suicide and Building a Culture of Respect for Life in 2011[26, 29]. However, among the Organization for Economic Cooperation and Development (OECD) member countries, Korean older adults have the highest suicide rate[30]. Given that depression has increased in older Koreans over the past decade, strategies that consider the characteristics of the baby boomer generation should be more developed to reduce the suicide rate.
Older Korean men, not women, showed an increase in the prevalence of depression over 10 years. While it is generally known that women are more susceptible to depression[31, 32], the recent increase in depression among older people has been driven more by men than women in Korea. Older Korean men, especially baby boomers, were primarily responsible for economic activities and excluded from caregiving duties in their families; therefore, they might have had relatively fewer opportunities to interact emotionally with family members[33]. As a result, after retirement, male older adults may have experienced a reduced role in the family and had difficulty seeking psychological support from their spouses and children.
In addition, older generations in Korea have been heavily influenced by Confucian culture, which emphasizes that men should assume economic responsibility in the family and have the filial duty of caring for their parents. This has also led to male adults being more respected as heads of households[25]. However, rapid sociocultural changes in Korea have eroded such traditional social norms. Younger Korean generations value equality over hierarchy and no longer have a special respect for their fathers. They also do not believe that they should support their parents financially and emotionally. These disparities and frustration may have contributed to depression in the current older population, especially in older men[26, 34]. As they still believe they must be financially responsible for their families, baby boomers who have experienced early retirement or economic instability may feel more psychological pressure. This explanation is supported by this study's findings that income level had a stronger effect on depression prevalence in current older adults than those who lived a decade ago.
Low-income status was associated with depression and suicidal behaviors, which was consistent with previous studies[35, 36]. The present study also showed an increased influence of income status on both depression and suicidal behavior in current older adults compared to a decade ago. Current older adults are a generation that believes that their social position and role are determined by whether or not they are economically stable. They are concerned and overwhelmed about preparing for their extended lifetime, as financial resources may become scarce as life expectancy increases[37]. Additionally, the baby boomer generation, with higher education levels and economic advantages compared to previous generations[23], may feel a greater sense of relative deprivation than the previous generation. As a result, old-aged individuals with low incomes may become more vulnerable to depression and suicidal behaviors.
In this study, the influence of employment status (having a job) on depression and suicidal behavior showed a tendency to increase in 2021 compared to 2011, although it was not statistically confirmed. Most previous studies demonstrated that employment was a protective factor for depression in later life[38, 39]. Our negative findings might be because the current older adults with jobs include many of those who were not prepared for retirement and were forced to take a job. In these cases, their jobs are usually low-paying and unstable, so being employed was unlikely to be a protective factor for mental health[40, 41]. Future research is needed to determine the influence of employment status, including the type of job, on the mental health of older adults.
Ten years ago, higher levels of education were associated with a reduced risk of depression and suicidal behavior. However, the opposite was true in 2021. Previous studies reported that a lower education level was a risk factor for depression and suicide[42, 43]. However, it should be noted that there has been a considerable change in the educational level of older Korean adults over the past decade. According to official statistics, only 32.9% of the general older population in 2011 had completed at least middle school[44], whereas the percentage of those with at least a middle school education was 57.6% in 2021[45]. The subjects in this study also had similar rates (27.6% in 2011 and 56.4% in 2021). While 9 or more years of education may have been a protective factor against depression and suicidal behavior in 2011, it might no longer do so in 2021. Rather, those with higher levels of education are more likely to have been in the workforce[46] and, therefore, may have experienced rapid changes in social position or early retirement. In other words, they may have been more exposed to the vulnerable factors mentioned above, which may have contributed to their poor mental health.
This study has some strengths. We compared the prevalence of late-life depression and suicidal behavior and the different influences of risk factors from 2 nationwide representative studies 10 years apart conducted by the same research group. Therefore, we could examine both period effects and cohort effects on the mental health of older Korean adults. Although the 2 types of effects were intermingled and could not be clearly isolated to explain changes over time for a generation or differences between generations at a point in time, the changing characteristics of older adults could only be explained by this study design. We also assessed depression using a structured diagnostic interview. While the prevalence rate of depression from self-reported surveys varies widely across the kinds of measurements, those using structured diagnostic tools are more accurate.
However, this study also had some limitations. First, there was an active COVID-19 pandemic during the 2021 study period, and the response rates were lower in 2021 than in 2011. In addition, the pandemic itself may have affected depression through social isolation among older adults. Therefore, it is important to consider these time-specificities when interpreting our findings. Second, the proportion of women in the 2 studies decreased from 2011 to 2021. This difference might have influenced the prevalence and factors associated with depression and suicidal behavior. However, considering that women have a probability of having depression, the prevalence of depression in 2011 could be overestimated. Therefore, it is plausible that the 10-year increase in the prevalence of depression might have been underestimated. Third, we compared the lifetime prevalence of depression and suicidal behavior, not one-year prevalences, due to the small number of subjects. However, older people tend to answer based on recent experiences, even when asked about their lifetime experiences. In particular, it has been reported that for negative experiences, such as depression, they are more likely to answer from recent experiences[47]. Finally, the 2 studies used different sampling methods. The 2021 study targeted entire national areas, while the 2011 study enrolled subjects in catchment areas, which might have affected the different response rates.
The prevalence of late-life depression in older adults has increased, whereas suicidal behavior has decreased over 10 years in Korea. The increase in depression was more prominent in older men than in older women, and vulnerable economic status was more associated with both depression and suicide in 2021 than in 2011. These findings should be considered when developing mental health policies for older adults.