ADHD is a chronic behavioral disorder of childhood onset (by age 7). ADHD affects children, adolescents, and adults. It is characterized by behavior that is hyperactive, impulsive, or inattentive. There are several different types of ADHD. Some children are primarily inattentive and do not display signs of hyperactivity. Others however, are hyperactive and/or impulsive. The rest exhibit a mixture of these symptoms.
The cause of ADHD is not known at this time, but brain chemistry, genetics, and environmental factors may all play roles in the development of ADHD.
It is estimated that almost 8% of American children have ADHD (about 1 to 3 children in every classroom of 30 children). About 60% of children with ADHD will continue to experience trouble related to their disorder into adulthood.
Because so many cases of ADHD are diagnosed in childhood, the information provided here is geared toward children.
About ADHD. Children and Adults with Attention-Deficit/Hyperactivity Disorder website. Available at: http://www.chadd.org/Understanding-ADHD/About-ADHD.aspx. Accessed October 4, 2017.
Attention-deficit hyperactivity disorder (ADHD). Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/condition/attention-deficit-hyperactivity-disorder-adhd. Updated June 2017. Accessed October 4, 2017.
Attention-deficit hyperactivity disorder (ADHD) in adults. EBSCO DynaMed website. Available at:https://www.dynamed.com/condition/attention-deficit-hyperactivity-disorder-adhd-in-adults. Updated December 27, 2016. Accessed October 4, 2017.
Attention-deficit hyperactivity disorder (ADHD) in children and adolescents. EBSCO DynaMed website. Available at:https://www.dynamed.com/condition/attention-deficit-hyperactivity-disorder-adhd-in-children-and-adolescents. Updated May 23, 2017. Accessed October 4, 2017.
Attention deficit hyperactivity disorder (ADHD). National Institute of Mental Health website. Available at: https://www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder-adhd-the-basics/index.shtml. Updated 2016. Accessed October 4, 2017.
Stern T, Rosenbaum J, et al. Massachusetts General Hospital Comprehensive Clinical Psychiatry. Philadelphia, PA: Mosby Elsevier; 2008.
Understanding ADHD: Information for parents. Healthy Children—American Academy of Pediatrics website. Available at: https://www.healthychildren.org/English/health-issues/conditions/adhd/Pages/Understanding-ADHD.aspx. Updated January 9, 2017. Accessed October 4, 2017.
What is ADHD? Kids Health—Nemours Foundation website. Available at: http://kidshealth.org/en/parents/adhd.html. Updated July 2014. Accessed October 4, 2017.
Last reviewed September 2018 by EBSCO Medical Review Board Adrian Preda, MD Last Updated: 10/20/2020