Main findings
Depressive disorders, anxiety disorders and schizophrenia are major public health concerns and contribute substantially to the global burden of disease.2 Compared with younger adults, older adults with common mental disorders have more physical illnesses, cognitive dysfunction, a less favourable prognosis and increased mortality.7 12 13 Using data from the GBD 2019, we systemically described the incidence and DALYs of depressive disorders, anxiety disorders and schizophrenia among people aged 65 years and older in China, India, Indonesia, Japan, Italy and Portugal from 1990 to 2019. This analysis allowed comparisons of the health loss attributable to these mental disorders over time across age groups, genders and countries. It yielded four key findings: (1) A considerable decrease in ASIR for depressive disorders in the older population was observed in aged countries, while an increase was observed in ageing countries between 1990 and 2019. Conversely, both anxiety disorders and schizophrenia in the older adults had declining ASIR trends in ageing and aged countries. (2) A substantial upward trend of ASDR for depressive disorders, anxiety disorders and schizophrenia in older populations was noted in ageing countries, while a downward trend was observed in aged countries from 1990 to 2019. (3) In 2019, the ASIR and ASDR for depressive disorders were more pronounced in older females, while the ASIR for anxiety disorders was higher in older males. This pattern was reversed for ASDR in anxiety disorders. Additionally, variations were evident in ASIR and ASDR for schizophrenia across countries. (4) People aged 65–70 years experienced a higher burden of depressive disorders, anxiety disorders and schizophrenia than other age groups among older adults over the past 30 years. This trend was particularly pronounced in ageing countries.
The incidence of depressive disorders, anxiety disorders and schizophrenia among people aged 65 years and older in China, India, Indonesia, Japan, Italy and Portugal increased continuously from 1990 to 2019, aligning with research results from the global burden of incidence for these conditions over the past 30 years.14–16 Notably, the highest incidence of all three conditions in older people among these six countries was observed in China, followed by India and Japan. China and India stand as the most populous nations globally, and Japan has the highest percentage of aged population in this century.4 Population ageing is occurring throughout the world, with a significant rise in the proportion of people aged 65 years and older in both ageing and aged countries.3 However, the ASIR of depressive disorders, anxiety disorders and schizophrenia in the older population displayed considerable variations across ageing and aged countries. In ageing countries, the ASIR for depressive disorders among older adults showed an upward trend from 1990 to 2019, while in aged countries a downward trend was observed, except for Indonesia and Japan. We observed a downward trend of the ASIR for depressive disorders in aged countries while an upward trend in ageing countries among the older population. Interestingly, this is not the case in a study focusing on the overall population. A previous study found a downward trend in the ASIR for depressive disorders at the national level in both ageing and aged countries from 1990 to 2017, with EAPCs of −0.59 in China, −0.74 in India, −0.13 in Indonesia, −0.35 in Italy and −0.27 in Portugal, with the exception of Japan (EAPC 0.42).14 These findings may be attributed to the different age groups of the participants, as our study focused solely on the older population, whereas the other study focused on all age groups. Factors such as rapid ageing in certain countries and potential higher risk of depression among lower-income populations might contribute to the observed increase in ASIR in ageing countries.17 Therefore, our results support the necessity to develop health policies and implement medication and psychological interventions for depression tailored to different countries.
During the past three decades, the ASIR for anxiety disorders among the older population aged 65 and over has declined in all countries analysed except for Indonesia. This contrasts with global trends reported in a previous study, which indicated a slight increase in the ASIR for anxiety disorders globally from 1990 to 2019 for all age groups.15 This discrepancy highlighted the importance of more standardised approaches in sample size and instrument selection across age-based studies. To our knowledge, this is the first study to demonstrate the downward trend of ASIR for anxiety disorders among people aged 65 years and over from 1990 to 2019. Indonesia’s divergence from other ageing countries in terms of depression and anxiety trends may be attributed to its lower degree of ageing and a less developed healthcare system.3 Consistent with previous findings of a slight decline in global ASIR for schizophrenia for all age groups from 1990 to 2017,16 both ageing and aged countries showed significant decreases in the ASIR of schizophrenia among the older population from 1990 to 2019.
The trend of DALYs for depressive disorders, anxiety disorders and schizophrenia among older adults in these six countries was in accordance with the global trend for all age groups, suggesting an increase in disease burden among mental illnesses from 1990 to 2019.2 Consistent with the incidence, China reported the highest DALYs for depressive disorders, anxiety disorders and schizophrenia in the older population, followed by India and Japan. However, the ASDR of these mental disorders in the older age group exhibited variations between ageing and aged countries. In concordance with the ASIR of depressive disorders in older adults, the ASDR for depression decreased in aged countries and increased in ageing countries from 1990 to 2019, with the exception of Indonesia and Japan. This discrepancy is potentially due to Indonesia’s lower degree of ageing and Japan’s higher degree of ageing in this research.3 The predicted burden associated with depressive disorders among older persons in China exhibited an upward trajectory, contrasting with the reported decrease in ASDR of depressive disorders in China and India between 1990 and 2017 and the reduction in ASDR of depressive disorders in Japan from 1990 to 2015 across all age groups.18–20 For anxiety disorders and schizophrenia in the older population, the ASDR increased in ageing countries and decreased in aged countries, with China being an exception. The observed downward trend of ASDR of anxiety disorders and schizophrenia in older adults in China is primarily attributed to a decline in the ASIR of these disorders from 1990 to 2019. However, despite this overall decline, the ASIR and ASDR for anxiety and schizophrenia experienced a notable surge in the last 3 years, contributing to a persistent increase in the absolute burden. This nuanced trend prompts the anticipation that the predicted burden of these mental disorders among the older people in China will continue to rise after 2019. This observation may be partly attributable to the exacerbated ageing demographics and heightened incidence rates amidst the global population in the backdrop of the coronavirus disease 2019 pandemic.21
An upward trend in ASDR of anxiety disorders in older adults was observed in Indonesia in accordance with the increases in ASIR of anxiety disorders. However, an increased ASDR and a decreased ASIR of anxiety disorders among the older population were observed in India. This phenomenon may be partly attributed to the second largest proportion of the populations and the poor healthcare system in India as the population ages.6 A previous study reported stable ASDR trends for anxiety disorders worldwide with an EAPC of −0.001 and for schizophrenia with an EAPC of −0.005 from 1990 to 2017 across all age groups.15 16 Some studies suggested a general increasing trend of the ASDR of schizophrenia with an EAPC of 0.038 in China over the last three decades.22 This inconsistency observed in reported ASDRs of anxiety disorders and schizophrenia emphasises the unique trends among older adults in ageing and aged countries. Future efforts are needed to better understand the persistence of depressive disorders, anxiety disorders and schizophrenia in the older population.
Significant disparities were observed in the burden of these mental conditions among people aged 65 years and older between males and females in ageing and aged countries. First, we identified a higher ASIR and ASDR of depressive disorders among the older population in these six countries in females than in males in 2019. This sex disparity is consistent with previous reports indicating a higher risk and greater burden of depressive disorders in females than in males.2 This study is the first to demonstrate that this trend is more pronounced in aged countries. Second, while global evidence suggests higher ASIR of anxiety disorders in females, our study reveals an opposite trend among individuals aged 65 years and older in all six countries analysed.23 24 Our results align with some previous studies on an older population (aged 75 years and older).15 However, the opposite trend was observed in the ASDR of anxiety disorders, with older females experiencing a higher burden than males. Our research findings supported the previous studies that the burden of anxiety disorders was greater in females than males at the national level.13 25 These findings highlighted the complexity of the relationship between anxiety disorders, gender and age. Third, the ASIR of schizophrenia was greater in older males than females in all six countries in 2019, consistent with emerging evidence indicating a higher incidence of schizophrenia in males worldwide.26 It was noteworthy that the ASDR of schizophrenia among older adults significantly varied by gender and country. In ageing countries, the ASDR for schizophrenia among the older population was higher in men than women, consistent with a recent global study on ASDR at the national level for all ages.16 Conversely, in aged countries, the trend reversed, with the ASDR being higher in women than men. This difference may be associated with an increased risk of comorbid substance use disorder in females than in males in aged countries.27
In the age group analysis across six countries, the incidence and DALYs of depression, anxiety and schizophrenia were highest among people aged 65–70. Notably, when considering the absolute burden of these conditions in older age groups, Portugal and Indonesia accounted for a more substantial proportion of patients aged 65–70. This aligns with previous research indicating that Portugal had the highest ASIR and ASDR of anxiety disorders,15 reflecting a consistent trend in overall mental disorders.2 In addition, the incidence rate of depressive disorders and anxiety disorders was highest in the age range of 65–79 years, consistent with patterns observed in a previous study on the incidence rate of depressive and anxiety disorders among those aged 67–81 years.28 Notably, to our best knowledge, this study is the first to find that Indonesia had the highest burden of incidence and DALYs for depressive disorders, anxiety disorders and schizophrenia among the older population in ageing countries, highlighting that Indonesia faced a severe burden of mental disorders in this context.
As the global population continues to age, depressive disorders, anxiety disorders and schizophrenia will continue to impose an increasing burden on the healthcare system.29 Urgent actions are needed to address the widespread issues of stigma and discrimination against individuals with these mental disorders in the older population, as they have far-reaching consequences.30 Future studies are warranted to provide insights to guide the development and implementation of specific policies for depression, anxiety and schizophrenia among the older population in more countries and regions.