People who suffer from depression may have noticed some amount of memory loss. This is not uncommon but is still not well understood as research progresses. In this article, I summarize ways depression affects memory, how to manage memory loss from depression and whether it can be reversed, and how to cope with memory loss caused by depression.

How Depression Affects Memory

As those who suffer from depression likely know too well, their ability to multitask, remember commitments and follow through on timely household tasks may seem overwhelming, if not impossible. Depression has a profound impact on many of our cognitive processes that contribute to memory, including paying attention, processing information and executive functions like memory retrieval.

The investigation of how depression causes memory loss is still in its early stages. Although clinically important, despite research done on various aspects for some years, the processes at work are still poorly understood. 

Depressed people generally have:

• Poor memory for positive events (which when asked to do so, can even make their depressed mood worse)
• Activated memory for negative events (they focus on the negative and can recall negative events better than positive ones)
• Weakened ability to recollect specific memories and when they do it’s general memories, not the details, say of a family celebration
• Less ability to remember future events such as a doctor’s appointment

Stress is a common trigger of depressive episodes. One promising line of inquiry suggests many memory deficits in depression are due to chronic stress, for three main reasons:

• Stress can suppress the creation of neurons in the hippocampus, the part of the brain responsible for short- and long-term memory and learning. Prolonged depression or stress leads to elevated levels of the “stress” hormone cortisol, which shrinks the hippocampus.
• It can also inhibit the production of dopamine neurons responsible for pleasure, satisfaction and motivation. 
• As well,it can sensitize the amygdala, the part of the brain responsible for linking emotions to memory, among other roles.

Research by Dillon and Pizzagalli [1] suggests that these phenomena could cause core aspects of memory disruption as they may:

• Disrupt pattern separation, the process by which highly similar stimuli or experiences in memory are represented in the hippocampus. And depression could reduce the performance of declarative memory, involving facts and events
• Disrupt the encoding and consolidation of positive experiences
• Bias retrieval towards negative events
• Promote overgeneralized fear responses

Depression can also negatively impact autobiographical memory—the memories of your life history which are core to your sense of self. This can be a very distressing part of being depressed.

There is a bidirectional relationship between depression and memory. Certainly depression affects memory, but memory issues likely make depression worse. Depressive episodes could be sustained given a bias for the brain to repeatedly retrieve painful, negative memories. Failure to encode and consolidate positive memories could reinforce the depressive mood that may have disrupted those processes to begin with [1]. 

Although not commonly considered a core symptom of depression, memory disruption may turn out to be critical to the negative sense of self that defines depression.

As well, rumination, dwelling repetitively on negative or upsetting people or events, is characteristic of depression. It makes it harder for those with depression to concentrate on other tasks and uses up neural resources that the brain could better spend on memory.

How to Manage Memory Loss from Depression

Can Memory Loss from Depression Be Reversed?

Depression is typically managed with counseling, exercise (which boosts dopamine and endorphins)  and possibly medication. Antidepressants such as the SSRIs can effectively reduce the sadness of depression but aren’t always as successful with the memory aspect. In fact, for some, they may worsen it. Despite improvement, patients may still have memory deficits. Early intervention is important to slow down the degeneration of the brain.

When to See a Doctor?

A person should definitely see a doctor if they are experiencing memory loss. Even the initial signs of memory loss could indicate a more serious issue. Depending on the age of the person, the doctor may need to decide if this is an early onset of dementia as it also involves memory loss, not necessarily caused by the memory loss of depression.

If the doctor feels it’s necessary, they may make a referral to a neurologist for further testing.

If the doctor believes that the person may have depression, ask them about techniques to improve memory and cope better. They may make a referral to a psychiatrist. Follow up with both if the memory loss worsens.

How to Cope With Memory Loss

There is little research on ways to cope with depression-related memory loss. Here are some ideas:

• Exercise: Benefits working memory, attention and processing speed
• Diet: Eat a healthy balanced diet of nutritious foods
• Cognitive games and exercises: Have fun while playing, usually on a computer
• Psychotherapy: Can increase brain activity
• Transcranial magnetic stimulation (TMS): Is a FDA-approved Non-invasive brain stimulation: method, increasingly used for depression
• Memory aids such as digital alarm clocks with notifications during the day, calendars, reminder apps, safety notes
• Create reminders for upcoming event
• Slow down to commit information to memory
• Work in a distraction-free environment where possible
• Focus on one thing at a time
• Stay in a regular routine
• Talk about your day as an aid to remembering
• Reduce distractions

Sources

[1] Dillon DG, Pizzagalli DA. 2018. Mechanisms of Memory Disruption in Depression. Trends Neurosci. 2018 Mar;41(3):137-149..

Viilines Z. 2023. Are depression and memory loss connected? Medicalnewstoday.com