Attention deficit hyperactivity disorder (ADHD) affects attention and motivation. It can also cause hyperactive or impulsive behavior. Some people with ADHD say that it can also cause tiredness.

Anecdotal evidence from adults sharing ADHD stories online suggests that many experience brain fog, low motivation, and fatigue.

Tiredness is not part of the official diagnostic criteria for ADHD, but a handful of studies do suggest that some people with ADHD experience fatigue.

Keep reading to learn more about the links between ADHD and tiredness. This article also provides information on other symptoms and treatment options.

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Hyperactivity is a hallmark of ADHD. This can cause a person to constantly be moving, talking, or fidgeting. Therefore, it might seem strange that ADHD could cause fatigue. However, for some people with ADHD, fatigue and hyperactivity are two sides of the same coin.

One 2019 study looked at a number of mental health symptoms in 97 nurses and 310 non-nurses. The study found a correlation in nurses who had ADHD and who experienced exhaustion. Exhaustion also correlated with the presence of several other mental health symptoms, including anxiety and depression. A 2017 study supported these general findings.

Researchers have not conclusively shown why ADHD causes fatigue in some people, but one possible explanation is the condition’s effects on dopamine.

ADHD can affect dopamine levels, making it more difficult for the body to respond to this important neurotransmitter. Dopamine plays an important role in motivation, reward, pleasure, emotional regulation, and executive function.

Low motivation or a low sense of reward from completing tasks may cause tasks to feel more exhausting. Also, decreased executive function can make it more difficult for a person to plan and organize their life, contributing to a sense of chaos that may cause feelings of overwhelm and fatigue.

There are several potential explanations for the connection between ADHD and tiredness.

ADHD can affect motivation. A person may find daily tasks overwhelming and struggle to complete them. This low sense of motivation can feel similar to fatigue, especially if a person feels unable to keep up with their responsibilities.

Additionally, the stress that ADHD may cause can feel exhausting, especially if a person’s symptoms are not well controlled. Missing deadlines, forgetting school work, and not meeting household demands may feel overwhelming or exhausting.

People with ADHD are also more likely to have another mental health diagnosis, such as anxiety or depression. Depression can also cause fatigue or excessive sleeping. Therefore, people with ADHD should be sure to seek proper medical advice. A doctor can assess their symptoms and consider the possibility that they may have another condition.

For some people with ADHD, fatigue is a symptom of their treatment rather than ADHD itself. For example, stimulant drugs can cause fatigue if a person stops using them suddenly, especially if they were taking high doses. Severe fatigue may also signal a stimulant overdose.

Brain fog can also be a symptom of ADHD. Researchers sometimes refer to this as sluggish cognitive tempo (SCT). Having SCT means that a person tends to move slowly, daydream often, appear disconnected from activities at school or work, work slowly, not seem very alert, and struggle to stay awake.

One 2020 study looked at 1,436 autistic children, 1,056 children with ADHD and no autism, and 186 neurotypical children.

The researchers asked mothers to rate their children on measures of SCT. The results revealed that SCT was more common in autistic children, 49% of whom scored 1.5 times standard deviations above the norm. Children with ADHD, however, also scored higher on this measure, at 40% for children with inattentive-type ADHD and 31% for those with combined ADHD.

This brain fog and SCT may happen for similar reasons to ADHD-related fatigue, including low motivation, high distractibility, difficulty with executive functioning, and issues with dopamine levels.

A number of other symptoms may look like fatigue or directly contribute to it. These include:

  • Difficulty listening: People with ADHD may constantly feel distracted or get bored easily. They may also frequently interrupt others or “zone out” at school or work.
  • Reward deficiency: Dopamine helps neurotypical people feel a sense of reward or accomplishment after completing a task. People with ADHD may not feel this sense of reward. This can make it hard to persist with challenging tasks and may cause a person to seem sleepy or disinterested even after an important accomplishment.
  • Avoidance of difficult tasks: Because it can be so difficult to focus on challenging tasks, some people with ADHD may avoid them.
  • Daydreaming: Daydreaming and other forms of distraction are common in people with ADHD. The person may appear checked out, disinterested, or chronically sleepy.
  • Feeling overwhelmed: Poor executive function can make it difficult for a person with ADHD to estimate how long a task will take. They may also find it challenging to plan or complete the task and remain focused on it when the time comes. This can make a person with ADHD feel overwhelmed, causing them to distract themselves, including by sleeping and daydreaming.

Although ADHD can present significant challenges, there do seem to be some benefits associated with having the condition, especially in relationships with others. Learn more here.

ADHD is treatable with the right support. Treatment generally works best when a person combines several options, such as classroom support and medication.

Some treatment options include:

  • Medication: Most people with ADHD take stimulant drugs such as methylphenidate. Some other drugs, such as antidepressants, may also help. It can take time to get the right drug dosage, so be sure to tell a doctor about all side effects and try to keep a log of how well the medication is working.
  • Trigeminal nerve stimulation: Trigeminal nerve stimulation is a type of noninvasive brain stimulation. The low electrical signals may reduce hyperactivity. The Food and Drug Administration (FDA) recently approved a trigeminal nerve stimulation device for children with ADHD who are not taking medication.
  • Therapy: Psychotherapy can help a person understand their diagnosis, develop coping skills, and manage their symptoms. It may also help with relationships. For example, couples counseling can help couples in which one partner has ADHD better manage and understand their symptoms.
  • Education and training: Parents and caregivers of children with ADHD need support and training to better manage the condition and understand the diagnosis. Family therapy, ADHD education programs, and parent training programs may help.
  • Accommodations: Having the right accommodations at work or school can greatly improve ADHD symptoms. For example, an adult may need a less distracting environment, while a child might need more time to complete their tasks. A number of federal laws in the United States require employers and schools to make reasonable accommodations.

The American Academy of Pediatrics (AAP) offers additional guidance for treating ADHD in children and teenagers. In children aged 4–6 years, the first line of treatment should be parent training in behavior management and classroom accommodations. Parents and caregivers should only add medication if these interventions do not improve the symptoms.

For older children, the AAP recommends a combination of behavior management, classroom accommodations, and medication.

ADHD manifests differently in each person who has it. Tiredness is just one of many symptoms that a person may experience.

The symptoms can change with time or circumstance, and a person may find that they need to change their treatment regimen as their symptoms shift. Receiving comprehensive care from a doctor and a mental health professional can help.

Parents or caregivers who think that their child may have ADHD should seek a comprehensive workup to rule out other diagnoses. They should then pursue a combination of treatments, including behavioral interventions and parental support.