Symptoms of depression include sadness and changes in mood. Depression, though, is a complex diagnosis that affects many aspects of functioning, including memory.
A 2018 analysis of earlier studies into the effects of depression and memory found that people with at least one symptom of depression self-reported memory complaints and other symptoms of depression. This suggests that memory loss could be a symptom of depression.
Some older people may mistake symptoms of depression as dementia. According to an older article, depression may cause a person to perform worse on brain function tests over time.
An article in the British Journal of Psychiatry indicates that some affective disorders, including depression, may increase the risk of dementia, especially if a person does not seek treatment.
People who have depression report struggling to recall particular memories. This suggests that depression can affect different types of memory, including declarative and autobiographical memories.
In a 2013 study, a group of young adults scored poorly in pattern separation. This is the method the brain uses to encode memories of similar events and other stimuli.
If pattern separation is impaired, people may become confused when thinking about where they have been, particularly if they have visited several similar places.
These findings support the idea that depression could reduce the performance of declarative memory, which involves the memory of facts and events.
The authors of the study hypothesize that depression may slow down the creation of nerve cells. This could make it difficult to form or access new memories.
One 2018 study published in Psychological Medicine found people with depression may also struggle to remember specific elements of their autobiographical memories — memories that focus on a person’s life history.
Researchers observed that people living with depression can over-generalize their autobiographical memories and recall little detail.
Researchers have also identified a link between depression and different types of memory loss, including impaired short-term memories and memory loss associated with dementia. According to the International Neuropsychiatric Disease Journal, some depression medications could also affect memory.
Short-term memory loss
Depression may cause short-term memory loss. A 2018 study on people with depression found that memory complaints had correlations with more severe symptoms of depression.
A 2014 meta-analysis of previous research found a clear association between depression and cognitive performance. People with depression had trouble with attention and memory.
They also struggled with executive function. Executive function is responsible for skills that help people focus on tasks, pay attention, and self-monitor their behavior.
Another 2014 study found that the effects of depression may affect memory even after treatment. This study found that people with a prior history of depression were more likely to remember negative adjectives from a list than people who had never experienced depression.
There may also be a link between depression and dementia, but scientists have found untangling this link challenging.
Sometimes caregivers and even doctors may mistake symptoms of depression, including memory loss, as dementia in older people. However, a 2010 analysis indicates that this may not be a mistake.
In many cases, the cognitive impairments that some older people experience with depression could be an early warning sign of dementia.
The researchers state that depression could be an early symptom of an underlying neurodegenerative condition.
Other research has found that people with depression may have a lower volume of gray matter. For instance, a 2013 paper details gray matter changes in people with depression. Gray matter volume declined in areas of the brain associated with emotion and working memory.
People with dementia may also have decreased levels of gray matter. This suggests that depression and dementia might have similar structural effects on the brain, potentially causing some of the same symptoms.
A 2019 study looked at data from the National Child Development Study, a long-term study of children into adulthood. It found that people who had symptoms of depression in their twenties were more likely to have poorer immediate memory and delayed memory when they reached 50.
This correlation does not mean depression causes memory loss later in life, as other factors, such as individual differences, could explain this phenomenon. Scientists must do more research to understand the link between depression and dementia.
Researchers have also identified a link between antidepressants and memory loss.
Tricyclic antidepressants may increase the risk of memory problems in some people. Similarly, a 2016 analysis found that people taking selective serotonin reuptake inhibitors (SSRIs) also experienced a decline in memory function within 8 weeks of starting treatment.
More research might clarify whether this decline continues or improves after the body adjusts to the medication.
Very little research has evaluated strategies for treating memory loss in people with depression. For some people, treating depression may ease memory loss. A healthcare provider can help a person compare treatment options and track changes over time.
Other strategies may also help. Those include:
- creating reminders for upcoming events
- slowing down to commit information to memory
- working in a distraction-free environment where possible
- focusing on one thing at a time
- using digital calendars for automatic notifications
A person who has depression and memory loss should not assume that depression is the cause, particularly if the memory issues interfere with daily functioning. Dementia, head injuries, infections, and other causes may also damage memory.
If a doctor thinks memory loss is a problem, they may recommend a person takes some memory tests. A doctor might also recommend additional testing, such as a brain magnetic resonance imaging (MRI) scan to check for brain injuries or blood work to assess for signs of infection.
A person should always see a doctor for memory loss because even subtle memory loss may signal a more serious problem.
If a doctor thinks that depression is the culprit, consider asking about strategies to improve memory and referral for psychiatric treatment. Follow up with the doctor if memory loss gets worse or interferes with day-to-day life.
The outlook for memory loss and depression depends on the cause. Some people find that their memory loss improves with treatment, or when switching to a different antidepressant. However, when depression is the cause, memory loss does not typically get worse.
When a neurodegenerative condition causes memory loss, symptoms may steadily worsen, eventually causing other cognitive problems.
When a person experiences memory loss, they may feel scared and avoid seeking treatment. However, it is essential to speak to a doctor who can ease a person’s worries, determine why they have memory loss, and offer a range of treatment options.