Attention Deficit Hyperactivity Disorder

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The National Institute of Mental Health (NIMH), a component of the National Institutes of Health (NIH), is the nation's leading federal funder of research on ADHD

What is attention deficit hyperactivity disorder?

Attention deficit hyperactivity disorder (ADHD) is a neurobehavioral disorder marked by trouble controlling impulsive behavior, difficulty paying attention, or overactivity. It is one of the most common neurodevelopmental disorders of childhood. ADHD interferes with a person's ability to stay on a task and maintain focus. The person may act without thinking or have difficulty with self-control. Some of the warning signs of ADHD in children include:

  • Failure to listen to instructions and miss details
  • Inability to organize oneself and schoolwork
  • Trouble paying attention to and responding to details
  • Restlessness
  • Fidgeting with hands and feet
  • Talking too much
  • Leaving projects, chores, and homework unfinished

Some people with ADHD have symptoms related to hyperactivity/impulsiveness, while others may be mainly inattentive. Some people have a combination of both types of symptoms. There are several types of ADHD, which is usually diagnosed in childhood, although the condition can continue into the adult years.

The causes and risk factors or ADHD are unknown although genes and a combination of environmental factors may play a role. There is no cure for ADHD, but medicines can help decrease impulsivity and hyperactivity and increase attention. Other options include psychotherapy, education or training, or a combination of treatments.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one improve care for people with attention deficit hyperactivity disorder?

Consider participating in a clinical trial so clinicians and scientists can learn more about ADHD and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with ADHD at, a database of current and past clinical studies and research results.

Where can I find more information about attention deficit hyperactivity disorder?

The following organizations and resources can help individuals, families, friends, and caregivers of people living with ADHD: 

Children and Adults with Attention-Deficit/Hyperactivity Disorder (CHADD)
Phone: 301-306-7070 or 866-200-8098

Learning Disabilities Association of America
Phone: 412-341-1515


Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.