ADHD Facts and Statistics

Medically Reviewed by Smitha Bhandari, MD on August 25, 2022
4 min read

You might know someone who has been diagnosed with attention deficit hyperactivity disorder (ADHD) or possibly has it. But how much do you know about this most common childhood brain disorder? Find out how it affects adults, famous people who have it, and other facts and statistics.

It’s Far More Common Than Autism

ADHD is the top mental or developmental condition among children in the U.S. Kids under age 18 who have ADHD outnumber those who’ve been diagnosed with an autism spectrum disorder by almost 4 to 1.

Average Age at Diagnosis Is 7

ADHD symptoms usually show up between ages 3-6. Kids with more severe ADHD usually get diagnosed around age 5. Those with mild cases usually are found around age 8. Often kids with hyperactivity and impulsivity are diagnosed earlier than kids with inattention alone

3 in 10 Children With ADHD Have Symptoms That Last Into Adulthood

ADHD can get milder or change as kids grow. For example, hyperactivity may ease as they get older. But young adults with ADHD might have depression, mood disorders, or substance abuse problems.

The ADHD Brain Is Physically Different

Some parts may be smaller than normal, at least for a time. The frontal lobe, which controls impulses, organization, and focus, might mature more slowly in kids with ADHD.

A Child With ADHD Has a 1 in 4 Chance of Having a Parent Who Also Has It

ADHD tends to run in families. If you have it, you’re more likely to have a sibling or other close family members who also have ADHD. Some parents learn they have the disorder after their child is diagnosed.

Most Adults Who Have ADHD Don’t Know It or Aren’t Getting Treatment

This is in part because they very often have one or more mental, emotional, or behavioral disorders. Such conditions as anxiety, depression, autism, and dyslexia can mask the ADHD symptoms. So the true share of the U.S. adults with ADHD is likely much higher than the official estimate of about 4%.

Children Born in Late Summer or Early Fall May Be More Likely to Be Misdiagnosed

Kids whose birthdays are close to the cutoff dates for school enrollment are more often mistakenly thought to have ADHD than their peers are. The students may simply be a bit younger and less mature compared to their classmates.

Untreated ADHD Can Make It Harder to Hold a Job

Studies have found that employees with ADHD are 60% more likely to get fired. They’re also three times more likely than their co-workers to quit without warning.

ADHD Can Be an Advantage for Certain Careers

Some ADHD traits can be strengths in the right jobs. Research shows that people with the condition tend to be more creative, independent, or fast paced compared to others. Depending on the person, occupations like artists, fire fighter, teacher, advertising professional, and small business owner may be good fits.

Celebrities Who Have ADHD

You might already know some of these famous faces. They include Olympic swimmer Michael Phelps and gymnast Simone Biles, as well as singer Justin Timberlake. Here are some others:

  • Andre Brown. The NFL once suspended former New York Giants running back for flunking a drug test. Brown forgot to report he took Adderall, a prescription stimulant, for his ADHD.
  • Jim Carrey. The actor and comedian often speaks candidly about living with ADHD and depression.
  • Dean Kamen. This prolific inventor is the mind behind the Segway scooter, a slew of medical devices, and a portable water purifier to bring clean water to developing nations. Kamen has ADHD and dyslexia.
  • Solange Knowles. The singer and performance artist was diagnosed with ADHD twice. The first time, Knowles didn’t accept it. She’s become an advocate for better diagnosis of ADHD, especially in Black youths.
  • Audra McDonald. The only woman to win six Tony awards, this singer and actor was found to have ADHD as a child. McDonald says she’s glad her parents did not follow her doctor’s recommendation to medicate her.
  • Michelle Rodriguez. The Latina actor was expelled from five schools because of her ADHD. Rodriguez’s talents took off after she discovered acting.
  • Henry Winkler. Best known as “the Fonz” on TV’s Happy Days, Winkler is a busy director and producer. He also has dyslexia. Winkler channeled his personal experiences in creating his children’s book character Hank Zipzer, “the world’s greatest underachiever.”