Attention deficit hyperactivity disorder (ADHD) can have a big impact on your ability to think clearly.

In fact, ADHD can sometimes make you feel as though a fog has seeped into your brain. Your reaction time slows. It can be harder to recall information, process your thoughts, and find the right words to say what you want to say.

This article explains the relationship between ADHD and the condition known as brain fog. It describes which thinking abilities can be affected by ADHD and it discusses treatments that may help clear the fog.

What is brain fog?

“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 dealing with brain fog, you may have symptoms like:

• mental fatigue or sleepiness
• forgetfulness
• mind wandering
• a cloudy or daydreamy feeling
• an inability to concentrate or focus
• a feeling that you’re disconnected from reality
• distraction
• loss of motivation
• slow physical movement
• a feeling of overwhelm
• an inability to find words to express your thoughts

While fog in the natural environment can seem pleasant and relaxing, cognitive fog can be just the opposite. It can cause your productivity at school or work to drop. It can cause communication problems in your relationships. And it can quickly lead to frustration and anxiety — feelings some people with ADHD know very well.

Can ADHD cause brain fog?

Brain fog can happen for lots of reasons.

Research has shown that aging, traumatic brain injuries, central nervous system injuries — even dehydration and standing up for too long — can bring it on. Health conditions such as lupus, celiac disease, chronic fatigue syndrome, and COVID-19 can all cause temporary mental sluggishness.

People with ADHD sometimes experience brain fog, too. Here’s what the research says about the connection between ADHD and that foggy feeling.

Overlapping symptoms

ADHD is a difference in the way the brain develops during childhood. The condition sometimes lasts into adulthood, though the symptoms can differ as you get older.

Health experts at the Centers for Disease Control and Prevention (CDC) say there are three main types of ADHD:

• Hyperactive-impulsive can show up as the need to be active, in motion, and talkative much of the time.
• Inattentive can show up as the inability to focus, pay attention, and remember things.
• Combination presents with both high activity and cognitive symptoms.

Many of the symptoms of inattentive ADHD are the same as those you experience when you have brain fog. Forgetfulness, trouble concentrating, and difficulty following instructions are some examples of these shared symptoms.

ADHD-related sleep problems

About 25 to 55 percent of children with ADHD have sleep disturbances, and 43 percent of adults with ADHD have trouble sleeping, too. ADHD can keep you from falling asleep quickly and also cause you to wake up throughout the night, affecting both the quality and quantity of your sleep.

When your sleep is disrupted, you can’t think as clearly as you can when you’re rested. Studies show that people with ADHD and sleep problems experience more:

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

ADHD and sleep disturbances have a complex relationship. ADHD makes it harder to get enough good sleep. And when you don’t get enough rest, your ADHD symptoms can get worse. This pattern creates a cycle, so it’s important to treat both conditions.

Can ADHD medications cause brain fog?

Some of the drugs used to treat ADHD symptoms can cause side effects that feel like brain fog. These side effects can include:

• exhaustion or fatigue
• daytime drowsiness
• a feeling that you’re sedated

Some ADHD medications can also lead to sleep problems. You may not sleep as long as you once did. And it may take longer for you to wake up fully in the morning.

If you’re having side effects like these, you can talk with a healthcare professional about changing your dose or type of medication. They’ll be able to work with you to find the right medication balance that works for you.

It’s important to talk with your doctor before you change your treatment because stopping some medications too quickly can have harmful effects.

Neuroinflammation and brain fog

Health experts think that the term brain fog captures many of the symptoms people have when there is inflammation in the brain or nervous system.

Inflammation also plays a role in the development of ADHD. For example, early exposure to pollutants like cigarette smoke that cause inflammation can increase the risk of ADHD in young children.

It’s also known that people with ADHD have an increased risk of having other inflammatory health conditions like asthma and eczema.

People with ADHD often have higher levels of cytokines in their bodies. These proteins are part of the natural immune response, and a high cytokine count is a sign of inflammation. Researchers have found that a jump in cytokines can:

• lower your ability to pay attention
• raise your chances of making mistakes on thinking tasks
• slow your reaction time
• interfere with your working memory

More research needs to be done to understand exactly how ADHD, brain fog, and inflammation influence each other.

What to do about ADHD and brain fog

While there isn’t a cure for ADHD itself, treatment can help clear up that foggy feeling. Here are some options to discuss with a healthcare professional:

For many children and adults, cognitive symptoms respond well to treatment. The first-line medication treatments for ADHD include:

• stimulants, such as Adderall and methylphenidate (Concerta, Ritalin)
• nonstimulant drugs, such as atomoxetine (Strattera) and nortriptyline (Pamelor)

Dehydration can worsen brain fog symptoms. In studies, dehydration affected memory, attention span, fatigue, the ability to do “mental” work, and reaction time. When study participants drank plenty of water, these skills rebounded quickly.

You’ll want to drink up during the morning and afternoon, though, so you don’t have to wake up during the night to use the bathroom.

People with ADHD need to take extra care to be sure they’re well rested. Treating both ADHD and sleep problems can give you better results than treating ADHD alone.

In one study involving 244 children with ADHD, those who learned about good sleep habits had fewer ADHD symptoms and better daytime functioning than those who were treated for ADHD without addressing sleep problems. The benefits were still present a year later.

You can create better sleeping conditions by:

• making sure your room is dark, quiet, and cool
• putting away digital devices well 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 help your condition.

Regular exercise improves thinking abilities in people with ADHD, studies show. Activity boosts executive function, which is the set of skills that allow you to remember, plan, focus, and follow instructions.

All forms of exercise are beneficial. Cardio exercise, such as running, biking, or swimming, can help dispel ADHD brain fog in the short term, and it can have longer lasting cognitive effects. Exercise may be more effective for children than adults, according to some studies.

Takeaway

Brain fog is a popular term that refers to a sense of mental fatigue and a slowdown in your thinking abilities. People with brain fog have trouble remembering and processing information. They can also have slower reaction times and lapses of attention.

ADHD is one of several health conditions that can cause brain fog. Many ADHD symptoms mirror brain fog symptoms. Brain inflammation may be behind some of them. ADHD can also cause sleep disturbances that make brain fog worse.

Treatment with medication may improve some brain fog symptoms — but some medications may actually worsen mental fatigue.

Talk with a healthcare professional about which medications might best treat your symptoms. Getting plenty of water, rest, and exercise can also help clear away mental fog.