Does Depression Cause Memory Loss?

Depression is a common condition, with one in seven people experiencing this disorder in their lifetime. It is also associated with a high rate of recurrence, as 20% develop chronic depression. According to findings from 2010, depression in the US is responsible for a total incremental annual economic impact of over $200 billion.¹ ²

Depression can cause other issues in the brain, especially issues associated with cognition. Cognition refers to all the brain’s processes involved in remembering, learning, and using knowledge.

One of the signs of a major depressive episode is the inability to concentrate or make decisions. These complaints are very common for people with depression. 

Depression and memory loss: What is the connection?

Depression can affect memory when the brain is unable to function correctly. This can present in a lot of ways, including: 

• Indecisiveness

• Forgetfulness

• Stress or worry over small details

• Lack of attention to detail

So what is depression doing to your brain that makes you struggle more with your memory compared to someone who doesn’t have depression? 

The area of the brain that regulates stress is the hypothalamic pituitary adrenal axis (HPA axis). The HPA axis involves three brain regions: The hypothalamus, the pituitary gland, and the adrenal glands. These areas communicate with each other when you are under stress.

Scientists have linked HPA axis dysfunction with depression and anxiety, as well as the reduced cognitive function that is common in these diseases. 

Essentially, the hypothalamus, adrenal gland, and pituitary gland communicate in a series of feedback loops. The release of one chemical can cause the release or inhibition of other compounds within the brain. 

One of those chemicals is cortisol, your primary stress hormone. The adrenal glands release cortisol, which can bind to glucocorticoid or mineralocorticoid receptors. These specific binding sites enable cortisol to affect your brain. Researchers believe cortisol dysregulation causes the brain’s development of major depressive disorder. 

It is difficult to tell exactly what is going on in the brain of someone with depression because everyone is different. However, the most common difference in the brains of people with depression is increased cortisol, which is also common in people with impaired cognition. 

This would indicate that the main cause of impaired cognition in people with depression is cortisol dysregulation due to the HPA axis in the brain not working properly. 

Simply put, if you feel like depression has made you more forgetful, you could be correct. It could be worth bringing up to your doctor for investigation.

What is memory loss in depression called?

Memory loss in depression has a particular name: Depressive cognitive disorder or pseudodementia. This is when the brain’s cognitive and functional impairment as a result of depression mimics other neurodegenerative disorders.³

However, the name pseudodementia may be misleading. In older adults at risk of dementia, the development of depression with this cognitive impairment can be a precursor to actual dementia. However, not everyone with depression develops dementia, so we are still trying to understand more about this condition.

Depression's impact on memory

Medical professionals use a specific manual to diagnose mental health disorders. The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) lists cognitive impairment as a core symptom of depression. 

The DSM-5 includes symptoms such as difficulty with thinking, concentrating, or decision-making, along with the typical mood symptoms associated with depression.

Main causes of memory loss

Unfortunately, the exact causes of memory loss in humans are difficult to determine. This is partly because cognitive impairment as a result of depression isn’t very well understood yet, nor is depression. 

However, one study conducted with rats looked at the effect of psychological stress on the body. To achieve this, they used a common test in rat studies known as social defeat. This is when the scientists put rats through psychological stress with intruders in their habitats.⁴

The study found physical markers of this stress in the rats. In particular, the socially defeated rats were far more likely to have memory impairment, with more issues associated with long-term memory. 

The rats who had memory impairment also had some biochemical markers of a process known as oxidative stress. This is when some brain cells become damaged or die in specific areas. 

Some of these brain areas also cross over to the HPA axis. However, studies in rats are very difficult to replicate with human participants because of our physiological differences. 

Does untreated depression cause memory loss?

To summarise the above points, people with depression are at risk of experiencing cognitive impairment. People with depression could experience changes in executive function, issues with working memory loss, attention, and problem-solving.

Unfortunately, depression is a disease that we still don’t fully understand. Current research is working to discover more about how depression affects the brain, particularly in cases of cognitive impairment or executive functioning deficits. 

Research on depression and memory

Short-term memory loss

A review of the latest research shows depression can affect a variety of functions within the brain, not just short-term memory. However, people experiencing depression may notice short-term memory loss first, as it’s the most apparent. 

The cognitive impairments that manifest most often for people with depression are issues in: 

• Executive function

• Working memory

• Focused attention

• Processing speed

When you combine these, the end result could be a person who struggles to work, study, interact with others, and complete everyday tasks.

Knowing how depression can affect all areas of the brain, you can see how it results in the common complaint of short-term memory loss. When you struggle to pay attention, start activities, process information at an effective pace, and hold that information in memory, you can see how those symptoms would present as short-term memory loss.  

Dementia

Depression leading to dementia among older adults is a health concern that scientists are actively looking into and working on understanding. Depression accompanies neurodegenerative dementia in about 15–20% of cases. Unfortunately, we still aren’t sure what’s causing the link between depression and dementia. 

Some hypotheses suggest that depression changes neurological pathways, altering neurotransmitters or neuroendocrine factors. It may even come down to genetic or environmental factors. As it stands, we simply don’t know how the two conditions are related. However, depression and dementia are clearly linked in the older population.

Depression and risk of memory loss

The risk of memory loss associated with depression is fairly high. People with depression or psychotic depression are more likely to have cognitive function deficits, including the brain areas that work to create memory.

The risk of memory loss in students with depression is well-established. Because learning environments such as schools require the constant development of many new memories, these are the perfect locations to observe memory loss in people with depression. 

In particular, issues with short-term memory are more apparent in academic environments. These problems are often due to students feeling overwhelmed, exhausted, stressed, or burned out. When this occurs, stress weakens short-term memory functions. The brain becomes more survival-focused and focuses less on retaining information in memory. 

It is worth noting that this level of stress is by no means restricted to students. Anyone struggling with high stress may be more prone to developing depression with cognitive impairment. 

Is depression-related memory loss permanent?

In most cases, memory loss from depression is not permanent. This memory loss is due to the brain being too distracted by everyday tasks and stress manipulating the brain’s signals. 

By treating depression, you can lower your overall stress levels and alter the biochemical signals of your brain, restoring your previous functioning level. This should enable your brain to focus and retain short-term memories again.

Does depression cause brain damage?

In some cases, depression can cause injury to the brain, which researchers believe is specific to older adults. For most people, depression can alter the function and formation of neurological pathways within the brain, but it won’t cause brain damage.

Diagnosis

The criteria for diagnosing depression are in the DSM-5. Memory loss and cognitive impairment are core symptoms of depression, so your doctor might diagnose you with depression if you meet the other criteria.

How to manage depression-related memory loss

Unfortunately, scientific research has not specified how depression and cognitive impairment develop. This means we have relatively little information on treating depression when cognitive impairment is a prominent symptom.

However, doctors and scientists are working hard to provide answers to those with these co-occurring issues. One drug that they are testing is vortioxetine. One trial tested this drug in 602 patients with cognitive-impaired depression. The study discovered that it improved cognition among people with depression.⁵

This gives us hope that there are treatments out there that will become available over time. For now, you could seek psychotherapy or practice stress management exercises to try to decrease the emotional stress that may affect you.

Additionally, treating your depression with medication could prevent your depression from worsening, reducing the risk of declining cognitive ability.

When to see a doctor

You should see a doctor if you have symptoms of depression. If you have a history of depression and you notice changes in your mood or ability to concentrate and retain memories, visit your doctor. This is particularly relevant for older adults who have a higher risk of dementia. 

The lowdown

It may seem surprising, but depression can alter brain functioning to cause memory loss. This can occur due to a variety of factors, resulting in changes to cognitive functioning. 

Unfortunately, scientists aren’t exactly sure what causes depression-related memory loss. They believe it could be due to the way depression alters brain activity, specifically the functions of the HPA axis, which processes stress. 

If your depression has led to changes in your cognitive functioning, you may have developed depression-related cognitive issues. Focus on being kind to yourself and reducing your stress as much as possible. It’s wise to speak to a doctor about treatment options, including therapy and medication. 

You should always see a doctor if you experience any changes in brain functioning, especially if you already have a depression diagnosis.