Depression and memory decline: How they feed on one another

Depression causes memory problems via confusion. It worsens in older people.

Depression causes memory problems via confusion. It worsens in older people. Photo: Getty

It’s no surprise that people with depression also struggle with memory problems. Forgetfulness or confusion are bound to happen when your mind is weighed down and foggy.

This is why depression, and other mood issues such as anxiety, make work life difficult.

The ability to think clearly and make good decisions are out of reach when you’re in a black hole.

We’ve all had days like this. Your short-term memory is wonky for a while. When your mood lifts, your memory improves.

For older people, it’s more complicated

A new study from the University College London (UCL) has found that the impacts of depression on memory accelerate and deepen as we age.

The implication is that these memory troubles caused by depression become more entrenched. And the damage goes both ways.

Memory decline brought on by depressive symptoms accelerates in people over the age of 50. While poorer memory “is also linked to an increase in depressive symptoms later on”.

The study looked at 16 years of longitudinal data from 8268 adults in England with an average age of 64.

The researchers concluded that “depression and memory were closely inter-related, with both seeming to affect each other”.

What the researchers say

Senior author Dr Dorina Cadar, of the UCL Department of Behavioural Science and Health said: “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.”

On the upside, she said that the study found that interventions to reduce depressive symptoms may help to slow down memory decline.

Lead author Jiamin Yin, who graduated from UCL and is now a doctoral student at the University of Rochester, New York, said: “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.”

How does this happen?

The researchers say that depression might affect memory due to depression-related changes in the brain.

These include neuro-chemical imbalances such as lower levels of serotonin and dopamine.

Structural changes in regions involved in memory processing are also implicated. As are disruptions to the brain’s ability to re-organise and form new connections.

But memory impairments “also might arise from psychological factors such as rumination – that is, repetitive thinking or dwelling on negative feelings.”

However, experiencing memory lapses or difficulties in retaining new information “can lead to frustration, loss of confidence, and feelings of incompetence, which are common triggers for depressive episodes”.

Memory impairment may also disrupt daily functioning and social interactions, leading to social isolation potentially triggering depressive symptoms.

Dr Cadar noted that depression can cause changes in brain structures, such as the hippocampus. This region of the brain is critical for memory formation and retrieval.

“Chronic stress and high levels of cortisol associated with depression can damage neurons in these areas.”

However, further understanding of mechanisms linking memory decline and depression is crucial, she said, for developing targeted interventions. These would seek to improve mood and slow cognitive decline “in individuals with depression and memory impairment”.

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