Population ageing is seen as something of a slow-burning shift, and scholars and policymakers have been discussing the best ways to prepare and adapt for the future for several years. In fact, the Madrid International Plan of Action on Ageing was adopted by the United Nations in 2002, the same year that ELSA began.

At the same time, societies can experience shocks and crises that cause disruption in expectations: the COVID-19 pandemic being a clear example of this. In such circumstances, certain issues can gain prominence in public discourse, which further stimulate the need for robust research.

Depression in later life

A key area in which the pandemic has intensified discussions is around mental health. Although trends in mental health are shaped across the life course, later life is characterised by key experiences that may influence the risk for depressive disorders. Such experiences include retirement, the onset of chronic illness, spousal bereavement, or becoming an unpaid caregiver.

In addition, dementia has gained greater attention from policymakers in light of population ageing. Depression has been identified as a risk factor for dementia, while it also features as a symptom of dementia and cognitive impairment.

Along with Prof Paola Zaninotto and other colleagues on the ELSA team, I have been pursuing two streams of work to examine depression in these contexts, taking advantage of the innovation and richness of the ELSA data.

Later life transitions and trajectories of depression

To understand the role of significant life transitions on depression, our work takes advantage of 18 years of data collected in ELSA, tracking 6,890 people aged 50-69 at Wave 1 (2002/03) through to Wave 9 (2018/19). We assessed whether key transitions happened between waves, examining whether trajectories in the probability of depression were different before and after key later life events.

Our findings suggest that neither the onset of a chronic illness nor retirement have a major influence on how the risk for depression changes over time. We do see some evidence for a slight worsening in the risk for depression due to becoming an unpaid caregiver, but this change in trajectory is not statistically significant. In contrast, the loss of a spouse/partner as well as spousal/partner retirement are both associated with significant improvements in the trajectory of depression risk.

Dementia and depression over the COVID-19 pandemic

We have also looked at depression according to cognitive function, investigating changes during the COVID-19 pandemic. ELSA is uniquely suited to conduct this research, as the Healthy Cognitive Ageing Project (HCAP) module from 2018 provides a robust way to classify people according to cognitive function that uses objective tests rather than relying on existing diagnoses. The COVID-19 sub-study also provides responses at two time points during the pandemic, which can be linked to those provided before the pandemic.

In grouping people according to no cognitive impairment, mild cognitive impairment (MCI), or dementia, we estimated the average depression score for each group using ELSA Wave 9 (2018/19) and the two assessment points of the COVID-19 sub-study (June/July and Nov/Dec 2020), controlling for a range of demographic, socioeconomic, geographic, and health-related variables.

We saw increases in the estimated average score for depression across time for all three cognitive function groups. The differences among groups were particularly interesting. In 2018/19, the average depression score was significantly higher for those with dementia compared to the other two groups, and it was significantly higher for the MCI group compared to the no impairment group. By June/July 2020, depression scores were significantly higher for the no impairment and MCI groups than they were in 2018/19. However, there were no significant differences between the cognitive function groups at this time or at the Nov/Dec assessment.

Overall, this tells us that mental health, in terms of depression, worsened for older people during the pandemic, and people without dementia experienced an increase in depression that put them at a similar level of depression as those with dementia by Nov/Dec 2020.

From results to resolutions… and potential impact

The work briefly highlighted above has helped to address some important research gaps, made possible by the special features of ELSA. While generating robust findings is a vital part of the process to improve the experience of later life in England, impact requires sharing lessons learned. For this work, there are two significant lessons I identify that should be useful for future advocacy and interventions to reduce the impact of depression among older people.

First, the improved trajectory following spousal bereavement corresponds to the worsening trajectory up to the loss. This finding likely reflects a greater psychosocial pressure that people experience in the years up to losing their partner/spouse. While it won’t always be possible to know that partner loss is on the horizon, this suggests an opportunity to enhance the mental health support given to people whose partners are, for example, on a declining health trajectory.

Second, the findings over the course of the pandemic suggest a convergence among cognitive function groups in terms of depression risk. With mental health services already under pressure from demand, the findings underscore the significant increase among older people without dementia. Along with trying to meet this increased demand, support services will also need to ensure that people with dementia are provided equitable access.

Depression is not an inevitable consequence of ageing. In identifying key trends and areas of opportunity, our research highlights how evidence can help policymakers, advocates, and charities develop targeted interventions, strengthen community and social support, and plan for more effective resource allocation. It’s also important we realise that, as with many other health concerns, formal organisations and informal social support networks both have a role to play to ensure dignity and wellbeing in later life – something we as a society must continue to work towards.