Attention deficit hyperactivity disorder (ADHD) is classified as a mental health disorder that usually shows up during early childhood. ADHD can pose many challenges in everyday activities, but many people take comfort in the misconception that children with ADHD are smarter than those without the disorder. The fact is that intelligence and ADHD do not go hand-in-hand. Some people with ADHD might have higher IQs, but assuming that the two universally go hand-in-hand may be harmful because it can keep your child from getting the help they need.

What Is ADHD?

ADHD is often diagnosed around the age of 7, and is best known for hyperactive behavior and attention difficulties. According to the National Institute of Mental Health (NIMH), about 9 percent of U.S. children and 4 percent of adults have the disorder. The reason there are statistical differences is because some adults outgrow the symptoms. It is also more prevalent in boys.

Some of the most common symptoms of ADHD are:

  • impatience
  • constant motion
  • difficulty sitting still
  • constant talking
  • trouble completing tasks
  • inability to listen or follow directions when given instructions
  • boredom unless constantly entertained
  • interrupts other conversations
  • does things without thinking (or on impulse)
  • problems learning concepts and materials at school

The NIMH also classifies the disorder into three subtypes:

  • predominantly inattentive (more symptoms of inattention exist compared with hyperactivity)
  • predominantly hyperactive-impulsive
  • combined hyperactive-impulsive and inattentive (this is the most common form of ADHD)

In order to be diagnosed with ADHD, you must exhibit six or more symptoms.


There is much debate as to whether or not someone with ADHD automatically has a high IQ. There is even more debate as to what such a correlation really means. Depending on the severity of symptoms, ADHD can affect a person’s ability to function at school and at work. Everyday tasks can also be difficult. This can give off the impression that such an individual has a low IQ, when this is not necessarily the case.

According to a 2010 study published in Psychological Medicine, adults who had both a high IQ and ADHD were found to have overall less cognitive functioning compared to other participants who had a high IQ but not ADHD. A range of verbal, memory, and problem-solving tests were used in the study. One problem with this study, however, is the fact that no other control groups were used. For instance, there were no ADHD-only or low-IQ groups for comparison.

On the flip side, many people with ADHD seem to only focus their attention on something they enjoy doing. This can translate well into school or the workforce for some individuals. In such cases, it’s not that the IQ is low — it’s just that these individuals can only focus on things they care most about.

Another report published in a 2011 issue of Psychological Medicine further determined that IQ and ADHD are separate entities. The study claims that IQ can run in families much the same as ADHD, but having a relative with a high IQ doesn’t mean another family member with ADHD will have the same IQ.

Possible Issues

The ADHD diagnostic process can also pose problems when determining whether a child is “smart” or not. There is no one particular test that can accurately diagnose ADHD — instead, the process is based on long-term observations of the possible symptoms. Some other conditions, such as autism, might also be mistaken for ADHD. The disorder may also be seen in some children who have learning disabilities, since some people with ADHD have process difficulties.

Stimulants, such as Ritalin and Adderall, are the most common medications used to treat ADHD, and are quite effective. While this might sound like a contradiction, a stimulant is helpful in some cases because it helps to control brain functions by increasing focus. These drugs may reduce hyperactivity, too. Some people may also experience less impulsivity. Stimulants can make a huge difference for some children who experience school difficulties; when one can fully learn and take tests, then their IQs might increase because of their increased ability to focus on tasks involved in formal IQ testing.

The Bottom Line

As with other disorders, ADHD can’t properly predict IQ. Furthermore, “being smart” doesn’t always depend on a high IQ. The correlations between ADHD and IQ — both good and bad —are based on stereotypes and misconceptions. There are dangers associated with both: one who just assumes that someone with ADHD has a high IQ might not seek proper treatment. On the other hand, one who assumes an ADHD patient is not intelligent will overlook that individual’s potential.

It is important to treat ADHD and academics as separate entities. While one can affect the other, they are certainly not one and the same.