ADHD may be one of the many health conditions that cause brain fog. Medications you take for ADHD, sleep-related issues, and brain inflammation may also play a role. However, treatments exist.

Attention deficit hyperactivity disorder (ADHD) can have a big impact on your ability to think clearly. And no, it’s not just “in your head.”

ADHD may sometimes make you feel as though a fog has seeped into your brain. It can be harder to:

  • recall information
  • process your thoughts
  • find the right words to say what you want to say

This condition is known as neurofatigue and cognitive (“brain”) fog. Here’s how it can affect your abilities and how to treat it.

A note on ADHD and brain processing

Many people with ADHD experience quickened brain processing, or feeling as if their thoughts move too fast. On the other hand, some people may experience slow moving thoughts, or brain fog. Others may not experience a fog at all. Brain processing speeds with ADHD is highly variable from person to person.

“Brain fog” isn’t a scientific or medical term. Researchers sometimes refer to the experience as sluggish cognitive tempo — a temporary slowdown in your thinking abilities.

When you’re coping with brain fog, you may have symptoms such as:

Brain fog may cause drops in your productivity or communication problems in your relationships. And it can quickly lead to frustration and anxiety.

But it’s not permanent — you can clear the fog with the right treatments and help from a professional.

Your brain may process information and operate differently than someone who doesn’t live with ADHD. Some areas of your brain may be more active, and others less.

These areas may involve your:

  • memory
  • organization
  • focus
  • decision making ability

This activity and inactivity in your brain suggest that it may have difficulty engaging these areas when needed and disengaging them when not needed.

When disengaged, you may feel it’s hard to perform certain tasks that require concentration. This may contribute to the feeling that your brain has “slowed down.”

Brain fog doesn’t have just one cause. Causes may result from one or more circumstances and health conditions, including:

The brain fog experienced in the above conditions may feel different than ADHD-related brain fog but can still have impacts on functioning.

You may receive a diagnosis of one of three types of ADHD:

  • Inattentive: may involve an inability to focus, pay attention, and remember things
  • Hyperactive-impulsive: may involve the need to be active and in motion and excessive talking
  • Combined: may involve symptoms of both inattentive and hyperactive-impulsive ADHD

Many of the symptoms of inattentive ADHD are the same as those you experience when you have brain fog. Examples include:

  • forgetfulness
  • trouble concentrating
  • difficulty following instructions

The above symptoms, however, may also be due to your brain processing information too quickly or being distracted.

ADHD may keep you from falling asleep quickly and may cause you to wake up throughout the night, affecting both the quality and quantity of your sleep.

You can’t think as clearly as you can when you’re rested if your sleep is disrupted. A 2018 research review shows that people with ADHD and sleep disorders experience more:

  • inattention
  • fatigue and daytime sleepiness
  • errors in schoolwork
  • difficulty with language, intellectual functioning, information processing

ADHD may make it harder to sleep well. And if you don’t get enough rest, your ADHD symptoms may worsen. This pattern creates a cycle, so it’s important to treat both your sleep problems and ADHD.

Some stimulant medications used to treat symptoms of ADHD may have a side effect of changes in mood. This may include feeling “zombie-like” or:

  • zoned or spaced out
  • lifeless
  • no personality
  • foggy
  • flat
  • emotionless

Often this happens because your medication dosage may be incorrect. Speak with your doctor to correct your dosage, and do not stop taking your medication without your doctor’s orders.

ADHD medications may also lead to sleep problems, such as sleeplessness. It may take longer for you to wake up fully in the morning. A lack of restful sleep may contribute to your brain fog.

Speak with a mental health professional

If your ADHD medication is causing side effects, talk with your doctor about changing your dose or medication. Do this before you change your treatment on your own, as stopping some medications too quickly may have harmful effects. Your doctor will work with you to find a treatment plan that works.

Health experts think brain fog captures many symptoms you may have if you have inflammation in your brain or nervous system.

Inflammation may also play a role in the development of ADHD. Prenatal exposure to environmental pollutants and cigarette smoke may cause inflammation and increase the risk of ADHD in young children.

You may also have an increased risk of other inflammatory health conditions, such as asthma and eczema, if you live with ADHD.

Research from 2018 has found that children with ADHD may have higher levels of pro-inflammatory cytokines in their bodies.

Cytokines are part of your body’s immune response. They can be anti- or pro-inflammatory. According to a 2020 research review, high pro-inflammatory cytokine activity may impair memory and learning.

More research is necessary to understand exactly how ADHD, brain fog, and inflammation influence each other.

There isn’t a cure for ADHD itself, but treatment can help with symptoms you experience. Some options to discuss with a mental health professional include:

Medication

For many children and adults, cognitive symptoms respond well to treatment. Medication treatments for ADHD include:

Hydration

Dehydration may worsen brain fog symptoms. In studies of adults and children, dehydration was associated with:

  • decreased brain function
  • lower working memory
  • lessened ability to efficiently shift attention between tasks

Try to avoid drinking water at least 1 to 2 hours before bed so you don’t have to wake up during the night to use the bathroom.

Sleep hygiene

Take extra care to be sure that you’re well rested. Treating both ADHD and sleep problems can give you better results than treating ADHD alone.

In a 2019 study of 244 children with ADHD, compared to those who only received treatment for their ADHD and not sleep problems, those who also learned about good sleep habits had:

  • fewer ADHD symptoms
  • better daytime functioning

You can create better sleeping conditions by:

  • making sure your room is dark, quiet, and cool
  • putting away digital devices a couple of hours before bedtime
  • limiting beverages, especially those with caffeine, late in the day

If you think you may have a sleep disorder, talk with a healthcare professional about whether a sleep study would benefit you.

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Physical activity

Regular exercise improves thinking abilities in people with ADHD, a 2021 study shows. Activity boosts executive function, skills that allow you to:

  • remember
  • plan
  • focus
  • follow instructions

Brain fog is a common term (but not medical or scientific) for mental fatigue and a slowdown in thinking abilities. It may cause difficulty remembering and processing information, slower reaction times, and lapses of attention.

ADHD is one of several health conditions that may cause brain fog. Many ADHD symptoms mirror brain fog symptoms, but it’s worth noting that ADHD often causes your brain to “speed up.”

Brain inflammation, sleep issues, and medication side effects may also contribute to brain fog.

Talk with a healthcare professional about a treatment that addresses all of the underlying causes of your brain fog. Staying hydrated, resting, and exercising may help clear your brain fog.

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