Constantly exhausted? Easily irritated by the teasing joke your friend made? Can’t concentrate on that daunting project you’re working on?

Brain fog, which often comes along with depression, is a serious condition that can have harmful effects on all aspects of your life.

Depression Makes You Tired

Depression is one of the most common mental health struggles in the US. Some experiences that could stem from depression are hopelessness, excessive feelings of guilt, insomnia, and, of course: brain fog and fatigue.

Cognitive Dysfunction: aka Brain Fog

In the context of depression, brain fog is formally referred to as “cognitive dysfunction.” Over 85% of people with depression experience this symptom.

As anyone who’s experienced brain fog or depression knows, symptoms of cognitive dysfunction can include:

  • problems with planning and coordination
  • difficulty remembering things
  • slow reactions to your environment
  • trouble paying attention

Depression, brain fog, and fatigue, or chronic tiredness, go hand in hand. It’s a vicious cycle: when you have depression, brain fog makes you spend extra energy to get through the day, which in turn makes you feel even more tired. Then you feel ineffective, which worsens your depression even more and interferes with sleep. It’s a revolving door that breeds fogginess.

Or The Other Way Around?

The direction of causality hasn’t been determined, but there are 100% concrete links between inflammation, brain fog, and depression – these links may go beyond just the cognitive and emotional factors in depression’s brain fog.

Other diseases that may involve autoimmune and/or inflammatory processes also correlate with brain fog. (Think chronic fatigue syndrome, fibromyalgia, or rheumatoid arthritis.)

So some doctors and scientists now believe inflammation may be a significant root of depressive symptoms – though not the only one.

This would make depression and brain fog siblings, instead of parent and child — both results of the same underlying processes.

What Brain Fog Feels Like

We hear the term ‘brain fog’ a lot these days, but what exactly is brain fog? Brain fog isn’t a medical condition on its own but it can be a sign of several different medical conditions, including depression. It is a collection of symptoms, including memory problems, irritability, inability to concentrate, and poor motivation. It can feel like you’re losing control of your own brain.

If you’ve ever experienced brain fog, you’ll know that its intensity can vary from day to day, even from one minute to the next! On a brain-foggy day, you might feel like the outside world is moving too fast for you to keep up with.

It can also be extremely frustrating if you can’t remember the right word, or if you always forget whether you’ve locked the door in the morning. You know it’s just mental fog, you know it’s not who you are. But with long-standing depression, it starts to feel like you’ve just become slow and sluggish.

What Fatigue Feels Like

Fatigue, like brain fog, can be a product of many different physical and mental conditions. It can be very tricky to describe to others because it’s often mistaken as simply feeling tired.

But fatigue is much more than just tiredness. People experiencing fatigue often feel tired even after light exertion. Getting through an average day seems like a marathon. And waking ‘unrefreshed’ is a big indicator that your feeling dead may be a more complex issue.

How Depression Causes Brain Fog

Because mental fog can be a symptom of a variety of different medical conditions and not just depression, the relationship between the two isn’t entirely clear. We do, however, have some ideas.

Cognitive and Emotional Factors

Depression disturbs the balance of the ‘feel good’ chemicals in the brain, called serotonin, and can result in a chronic sense of sadness and lack of wellbeing. But that’s not the whole story.

Your upbringing can also set you up with a lack of self-compassion, which the helplessness of brain fog amplifies into a self-hating or hopeless thought loop. Studies show that these dejected emotional states can relate to elevated inflammatory chemicals that make you feel even more foggy.


Another suspect is depression medication, such as antidepressants. These pharmaceutical drugs work to restore the balance of chemicals in the brain and, hopefully, relieve depression symptoms.

Ironically, however, these medicines seem to contribute to brain fog as a side-effect because of the biochemical changes they cause in the brain. If you think that your antidepressants may be the real culprit, it is worth tracking when you experience a brain fog episode. If the brain fog follows shortly after taking your pills, then you might be onto something. Tracking your symptoms, in general, can help you figure out small ways to counter the fog.

How Does Depression Cause Fatigue?

Depression and fatigue go together, like your morning PB & J. The reason why the two are so interdependent is because of the underlying factors that simultaneously feed both.


Research shows that depression negatively affects the brain’s reward system by changing the the amount of dopamine, a neurotransmitter involved in feelings of pleasure, reward, and motivation. A disrupted reward system can make it hard to see the point in spending any energy, on anything, which manifests as fatigue.


Insomnia, which is characterized by trouble falling or staying asleep, is closely related to depression. The relationship is actually bi-directional. This means that insomnia increases the likelihood of depression because it deprives us of energy and sleep’s physical repairs. And being depressed, in turn, makes it harder to get a good night’s sleep, partly because of the restless cycle of negative thoughts. The end-product is, as you might’ve guessed, unbeatable fatigue.

Long story short, depression is tightly related to both fatigue and brain fog in a never-ending triangular relationship. But there are ways to break the spell!

Being open and honest about your struggles can be a crucial step in your recovery process. It allows you to track your symptoms and find ways to address them.

And an open attitude toward your struggle allows you to share your concerns with someone you can trust.

We’ll end on a note to those who love someone struggling with brain fog: remember that helping is just as important as being helped – if you think your loved one might be struggling, don’t be afraid to reach out for support. Recovery starts with these small steps.

Written by: Janan Mostajabi and Christina Beck