In a significant advancement in understanding the intricate relationship between mental health and cognitive function, a new study led by researchers at UCL and Brighton and Sussex Medical School reveals a bidirectional association between depressive symptoms and memory decline in older adults. Published in JAMA Network Open, the research analyzed 16 years of longitudinal data from 8,268 adults in England, with an average age of 64.
Key Findings
The study concluded that depression and memory are closely interrelated, with each affecting the other over time. Senior author Dr. Dorina Cadar from the UCL Department of Behavioural Science & Health and Brighton and Sussex Medical School stated, “It is known that depression and poor memory often occur together in older people, but what comes first has been unclear. Our study shows that the relationship between depression and poor memory cuts both ways, with depressive symptoms preceding memory decline and memory decline linked to subsequent depressive symptoms. It also suggests that interventions to reduce depressive symptoms may help to slow down memory decline.”
Lead author Jiamin Yin, now a doctoral student at the University of Rochester, New York, emphasized the practical implications of these findings: “These findings underscore the importance of monitoring memory changes in older adults with increasing depressive symptoms to identify memory loss early and prevent further worsening of depressive function. Conversely, it is also critical to address depressive symptoms among those with memory decline to protect them from developing depression and memory dysfunction.”
Study Details
The researchers utilized data from the English Longitudinal Study of Ageing (ELSA), focusing on community-dwelling adults aged 50 years or older. The study measured cognitive function through memory and verbal fluency tests, while depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. The analysis revealed that higher depressive symptoms were associated with poorer memory at the baseline and accelerated memory decline over time. Conversely, a steeper decline in memory was linked to an increase in depressive symptoms.
Interestingly, while less verbal fluency was linked to more depressive symptoms at the start of the study, changes in verbal fluency did not predict later changes in depressive symptoms, and vice versa.
Biological and Psychological Mechanisms
The research team suggested several mechanisms that might explain the observed bidirectional relationship. Depression might affect memory due to neurochemical imbalances, structural changes in brain regions involved in memory processing, and disruptions in the brain’s ability to reorganize and form new connections. Additionally, psychological factors such as rumination—repetitive thinking or dwelling on negative feelings—may contribute to memory impairments.
On the other hand, experiencing memory lapses can lead to frustration, loss of confidence, and feelings of incompetence, common triggers for depressive episodes. Memory impairment may also disrupt daily functioning and social interactions, leading to social isolation and subsequent depressive symptoms.
Dr. Cadar added, “Depression can cause changes in brain structures, such as the hippocampus, which is critical for memory formation and retrieval. Chronic stress and high levels of cortisol associated with depression can damage neurons in these areas. However, a further understanding of mechanisms linking memory decline and depression is crucial for developing targeted interventions aimed at improving mood and slowing cognitive decline in individuals with depression and memory impairment.”
Implications for Public Health
The study’s findings highlight the need for integrated assessment and treatment approaches in clinical practice. Regular memory assessments should be part of the evaluation for depressive symptoms in older adults, and addressing depressive symptoms in individuals with memory loss may help mitigate further decline in memory function. The researchers advocate for early intervention in depressive symptoms to slow down or delay memory decline in later life.
Support and Funding
This research was supported by the National Institute on Aging, the Economic and Social Research Council (ESRC), the National Institute for Health and Research (NIHR), Alzheimer’s Society UK, and Alzheimer’s Research UK.
References
- Yin, J., John, A., & Cadar, D. (2024). Bidirectional Associations of Depressive Symptoms and Cognitive Function Over Time. JAMA Network Open. https://doi.org/10.1001/jamanetworkopen.2024.16305
- University College London. “Depressive symptoms may hasten memory decline in older people.” ScienceDaily. www.sciencedaily.com/releases/2024/06/240611130411.htm
