Depression and memory are closely interrelated and influence each other, according to a new study by researchers at UCL (London’s Global University) and Brighton and Sussex Medical School. It has revealed that depressive symptoms are linked to a decline in memory in older people and, in turn, poorer memory is linked to an increase in depressive symptoms over time.
“It is known that depression and poor memory often occur together in older people, but it was not clear which came first,” said lead author Dr Dorina Cadar, from the Department of Behavioural and Health Sciences at UCL and Brighton and Sussex Medical School. “Our study shows that the relationship between depression and poor memory is bidirectional, with depressive symptoms preceding memory decline and memory decline linked to subsequent depressive symptoms. This also suggests that interventions to reduce depressive symptoms may help to slow memory decline.”
Researchers analyzed data from 8,268 adults with an average age of 64 collected over 16 years in the English Longitudinal Study of Ageing (ELSA), in which a representative sample of the population in England answers a wide range of questions every two years.
The results have been published in JAMA Network Open and show that people who had more depressive symptoms at the start of the study were more likely to experience faster memory decline in the future and that people with worse memory were more likely to have depressive symptoms later on.
Furthermore, participants who experienced a greater increase in depressive symptoms during the study were more likely to have a more pronounced memory decline at the same time, and vice versa: those who had a more pronounced memory decline were more likely to have a more acute increase in depressive symptoms.
Changes in the brain that can impair memory
The research team suggested that depression might affect memory because of depression-related changes in the brain that include neurochemical imbalances (e.g., lower levels of serotonin and dopamine), structural changes in regions involved in memory processing, and alterations in the brain’s ability to reorganize and form new connections.
These experts also noted that memory problems could arise from psychological factors such as rumination – repeatedly thinking or focusing on negative feelings. On the other hand, people who experience memory lapses or difficulties retaining new information may feel frustration, loss of confidence and feelings of inadequacy, which are common triggers of depressive episodes. Memory impairment can also affect daily functioning and social interactions, which could lead to social isolation and trigger depressive symptoms.
“It is essential to develop specific interventions that improve mood and slow cognitive decline in people with depression and memory problems”
“These findings highlight the importance of monitoring memory changes in older adults with increasing depressive symptoms to identify early memory loss and prevent worsening of the depressive condition.” “On the other hand, it is also crucial to address depressive symptoms among those with memory impairment to protect them from developing depression and memory dysfunction,” said Jiamin Yin, another of the lead authors.
“Depression can cause changes in brain structures such as the hippocampus, which is crucial for memory formation and retrieval. Chronic stress and high cortisol levels associated with depression can damage neurons in these areas. However, it is critical to better understand the mechanisms linking memory impairment and depression in order to develop targeted interventions to improve mood and slow cognitive decline in people with depression and memory problems,” concludes Dr. Cadar.
