Can depression cause a loss of IQ?

In this article we will discuss the question of whether depression can impact intelligence and lower Intelligence Quotient of people who are affected by the disorder.

Can depression cause a loss of IQ?

Depression might not directly cause a loss or decrease in IQ scores however, it does cause a major impairment in cognitive functioning which can make it seem that depression has impacted one’s intelligence. 

A few areas of cognitive functioning that is impacted by depression include:

  • Deficits in attention
  • Memory impairment
  • Execution finditonig impairment
  • Decision making difficulties

When we consider depression or Major depressive disorder and its impact on a person we are well versed with the idea that it impacts a person’s mood and behaviour. 

We think of a person feeling sad and down for long periods of time; losing your energy and your interest in things you used to enjoy; sleeping too much or too little, or eating too much or too little. 

However, beside these symptoms, depression can actually change your ability to process information, think, and make decisions. It can also impair your attention and memory. Depression can also limit your cognitive adaptability- meaning your ability to change the way you think based on changing situations. 

Depression can impact the way you concentrate, pay attention, focus, and at times can also lead to severe dysfunction which can make it nearly impossible to meet the demands of your life. 

Let us take a closer look at depression and how it impacts cognition. 


Depression is now considered a deadly condition likened to an epidemic. WHO estimates that there are millions of people who live with the condition and are affected by it worldwide. 

Unfortunately there are many people who struggle with this condition without the awareness to be able to identify and seek treatment due to lack of education and stigma. 

Depression can have a myriad of causes. There is no one main cause to it. Because there is also the possibility of brain chemicals known as neurotransmitters and it’s imbalance that has been linked to depression, it is a possibility that the physiology of your brain could be part of it. 

Other than this factor, we also have genetic bulnerabiiyt such as having depression or other mental illness being part of the family history, life stressors that act like triggers for the depression to develop such as trauma, loss, failures, stress, abuse, and unwanted changes in one’s life. 

While there has been growing awareness about mental health and mental disorders, not many people are aware about the extent of its impact on cognition. Let us take a look at how depression impacts cognition.


Impact of depression on cognition

It has been long understood that deficients in the ability to think and concentrate is a symptom of depression ever since Major depressive disorder had been introduced and recognised as a mental disorder.

Cognitive abilities are identified as one of the functioning impairments that are observed even after the individuals affected by MDD are treated for their mood symptoms. 

This means that even if people see that there are substantial improvements in their mood, they still experience impairment in various areas of their lives due to impairment of their cognition. 

There have been multiple reviews and studies that have studied cognitive processes in people who are affected by MDD. These studies have found that:

  • Depressed people score lower in cognitive tasks as compared to healthy individuals. 
  • Cognitive deficits can be observed in individuals whose depression has remitted 

Cognition is such a big part of the recovery process that the higher the amount of cognitive deficits observed, the more severe the symptoms and more likely the rates of relapse. 

There have been many studies and self-reports that explore the cognitive effects of depression and how it can negatively impact a person’s cognitive abilities. 

However, since testing IQ is done in clinical settings it does not give an accurate representation of a person’s functioning in real-life conditions but there is enough evidence to show that there is substantial impairment that is involved.

Let us take a look at how depression impacts cognitive functions:

Deficits in Attention

Many people who suffer from depression may also have been diagnosed with another mental health disorder, including attention deficit disorder (ADD).

In an attempt to study whether low cognitive functioning is a precursor of depression or a consequence of depression, researchers tested their hypothesis on a sample of over 1000 adults.

The results of their study found that their findings did not support the “Scarring hypothesis” which suggests that MDD leads to persistent cognitive deficits following disorder onset.

The study found that the study members with a past history of MDD show greater cognitive decline when MDD was accompanied by other comorbid psychiatric conditions. 

People with depression who also have comorbidity with ADD are also more likely to experience attention problems. Researchers don’t yet know exactly what causes attention problems in people with depression, but there is a correlation between the two. 

Memory Loss

If you’re suffering from depression, you may also have trouble with memory loss. It’s a fairly common symptom of depression, and people often are unable to recall minor daily details like what they ate for lunch, what they did at work, and they may forget the details of a significant event. 

Executive function impairment

Depression may also impact your executive function, which affects your ability to process information. Executive function impairments may make it difficult to complete simple tasks like paying bills or remembering to return a phone call. 

A person who is depressed can find it difficult to manage time, shift focus, organise, and remember other responsibilities of their life. This is all because of significant impairment in executive functioning. 

Because it is so hard to get things done, it becomes difficult for people affected by depression to meet the demands of their life. 

Decision-making becomes difficult

Depression can make it extremely difficult to make decisions- even simple ones like what to eat for dinner. Depression often leads people to make decisions specifically to avoid anxiety. 

People with depression often feel hopeless and as a result, feel like their decisions and planning will not work. This often leads to less efforts made to process information, generate more ideas, and think less. This can lead to the decisions that are made to be less than optimal.

These forms of impairment in one’s cognitive abilities when they are affected by depression not only involves IQ scores but also cognition as a whole. 

People with depression often struggle with managing life stressors which can impair their ability to process information, and reason rationally. 

Due to the impact depression has on rationalizing, a person might be observed to be or may even self-report to be experiencing a loss of IQ. However, studies have not found significant change in IQ scores before and after depressive episodes only. 

Rather there has been found to be a link between depression and change in IQ scores where there is comorbidity. It is also to be mentioned that depression not only impacts one’s IQ- reasoning and problem-solving ability but also intelligence elements as well such as- memory, comprehension, and understanding. 

Treating Depression related cognitive impairments 

Antidepressant medications are mainly administered  to help improve mood and increase the ability to participate and engage in their lives actively. 

It’s also worth noting that different parts and processes of the brain are responsible for cognitive (versus emotional) functioning which makes it difficult for target treatments to be used for cognitive impairment. 

In an attempt to help treat depression related symptoms and consequences, cognitive rehabilitation is now an emerging aspect of treatment and therapy. 

One such strategy involves problem-solving treatments that can train people how to improve their problem-solving skills.

Another is Cognitive behavioral therapy that can teach people to recognize and challenge distorted thinking patterns. 

Cognitive remediation therapy uses practice drills to improve memory and executive functioning. 

Studies suggest that combining these behavioral interventions with antidepressants may ked to better results for improving depression-related cognitive impairments.


In this article  we have discussed the question of whether depression can cause a loss or lowering of IQ scores and overall intelligence by attempting to understand how depression impacts cognitive functioning.


Frequently asked questions related to “Can depression cause a loss of IQ?”

Is depression related to intelligence?

Studies have found that higher IQ is associated with the higher likelihood of a person becoming depressed due to various cognitive patterns of thought such as rumination.

How does depression affect emotional intelligence?

People with major depressive disorder  have been shown to have difficulties understanding and managing their emotions. They may also experience apathy and the inability to feel for others and themselves. 

Is there a correlation between intelligence and depression?

Studies have also found that higher IQ is associated with more mental illness, including depression, anxiety, and bipolar disorder.

What brain abnormalities are associated with depression?

Structural and functional abnormalities in the areas of the main subcortical limbic brain regions- namely the amygdala, hippocampus, and the dorsomedial thalamus have been found in depression.

Is neuroticism linked to intelligence?

Neuroticism is a risk factor for selected mental and physical illnesses and is inversely associated with intelligence meaning that a person who is more intelligent has a lower likelihood to engage in neuroticism related patterns of thought and behaviour.  Intelligence appears to interact with neuroticism and mitigate its detrimental effects on physical health and mortality.

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