What Is the Difference Between ADD and ADHD?

Medically Reviewed By Karin Gepp, PsyD
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Before the 1980s, attention deficit hyperactivity disorder (ADHD) was called attention deficit disorder (ADD). Doctors added the word “hyperactivity” when there were also signs of impulsive or hyperactive behavior. However, in 1987, as researchers’ understanding of the condition improved, the American Psychiatric Association published an updated version of their Diagnostic and Statistical Manual of Mental Disorders, where they replaced the term “ADD” with “ADHD.”

There are over 6 million children in the United States with a diagnosis of ADHD. Healthcare professionals are three times more likely to diagnose ADHD in boys than girls. About 4.4% of adults in the U.S. also have ADHD.

Read on to learn more about the differences between ADD and ADHD.


a doctor is smiling and talking to a child with adhd
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“ADD” was once the name doctors used to describe ADHD.

Scientists used to believe that hyperactivity was not a common symptom of the condition. Therefore, they did not include the term “hyperactivity” in the name but instead split ADD into two distinct groups. These were ADD with hyperactivity disorder and ADD without.

This was the case until 1987, when researchers found that hyperactivity was indeed a common symptom of the condition. Therefore, they stopped splitting the condition into these two groups and instead added “hyperactivity” to the name. The three common symptoms that this new term, “ADHD,” encompassed were:

Nowadays, there are three main types of ADHD. These are:

  • predominantly inattentive type ADHD
  • predominantly hyperactive impulsive type ADHD
  • combined type ADHD

Some people still use the term “ADD” to refer to predominantly inattentive type ADHD.

Predominantly inattentive type ADHD

Sometimes, people mistakenly refer to predominantly inattentive type ADHD as ADD.

Predominantly inattentive type ADHD is the most common ADHD presentation, and in children, it affects young girls more often than boys.

Symptoms of this subtype can include:

  • experiencing difficulty with paying close attention to details
  • making mistakes others may see as careless
  • experiencing difficulty with staying focused for long periods
  • appearing not to listen
  • struggling to follow instructions
  • experiencing difficulty with organization
  • avoiding tasks that require sustained concentration
  • losing things
  • being easily distracted
  • seeming forgetful during daily activities

Predominantly hyperactive impulsive type ADHD

To receive a diagnosis of predominantly hyperactive impulsive type ADHD, children must meet a different set of criteria over a period than the symptoms of predominantly inattentive type ADHD.

These symptoms include:

  • fidgeting and tapping the hands or feet
  • squirming in their seat
  • wanting to leave their seat when they have been told to stay seated
  • running or climbing in situations where they should not, or feeling restless in adults
  • playing loudly
  • feeling uncomfortable being still and seemingly always “on the go”
  • talking a lot
  • completing other people’s sentences or answering questions for them
  • finding it hard to wait for their turn
  • interrupting other people in conversation or during activities

Combined type ADHD

Adults or children who show a mix of symptoms from the criteria for predominantly hyperactive impulsive ADHD and predominantly inattentive type ADHD may have combined type ADHD.

Adults may experience a smaller variety of symptoms than children to receive a diagnosis.

Symptoms of ADHD can change over time. This means children or adults may fit into different categories at different times.

Learn more about the symptoms of ADHD.

How to prepare for a doctor’s appointment

It is important to discuss a possible ADHD diagnosis with a doctor. Other disorders may have symptoms that overlap or are similar, and doctors should rule these out before diagnosing ADHD.

There could also be other disorders that occur along with ADHD. When more than one diagnosis occurs at the same time, these are called “concurrent diagnoses.”

Questions a doctor may ask

Some of the questions your doctor may ask include:

  • What behaviors have you noticed?
  • How long have these behaviors been present? (Generally, ADHD symptoms must be present for at least 6 months.)
  • How is the child doing in school? (For adults, doctors may ask questions about work life or daily activities.)
  • What have the child’s teachers or adults’ peers said about the behavior?
  • Is the child or adult having difficulty just in school or work, or elsewhere like while with friends or at home?
  • Have there been any significant changes in the child or adult’s life, such as a divorce, a move, or anything that could contribute to the behaviors?
  • How is the child or adult sleeping?
  • Does anyone else in the family have ADHD or a similar disorder?

It can be helpful to make a list of answers to these questions before the appointment so you are sure not to miss anything.

Learn more about talking with a doctor about adult ADHD.

Physical examination

The doctor will do a physical examination to check vision and hearing and may order tests to rule out any physical or mental health conditions that could possibly lead to a different diagnosis. For example, sometimes children with suspected ADHD have hearing problems.

Up to two-thirds of children with ADHD have a coexisting condition. A doctor will check for these too. Coexisting conditions may include:

Read more in our ADHD appointment guide.

What else to expect

Other things your doctor may do include:

  • asking teachers, other adults, or both to fill out evaluation forms or assessments
  • referring you or the child to a psychologist for psychological testing
  • referring you or the child to a neurologist to rule out any disorder affecting the brain

Not all doctors are comfortable treating ADHD, so they may refer people to an ADHD specialist for medications and other treatments.

Learn six treatment options for ADHD here.

Causes of ADHD

Doctors are not sure exactly what causes ADHD. However, there is a lot of research suggesting ADHD has strong genetic links.

In addition to genetic links, environmental factors that could lead to ADHD include:

  • having experienced a brain injury
  • having a premature birth or low birth weight
  • having come into contact with lead or pesticides in early childhood

The following factors may worsen the symptoms of ADHD in some children:

  • sugar
  • excessive television time
  • stress


“ADD” is a term people often use interchangeably with “ADHD,” but it became outdated in the late 1980s. Some people may still use it to describe a subtype of ADHD called predominantly inattentive type ADHD.

A diagnosis of ADHD has historically carried stigma. However, the condition is often manageable with a combination of medication and lifestyle changes. Sometimes, just having the diagnosis can be helpful, as it can explain many behaviors.

If you suspect that you or a child may have ADHD, do not delay seeing a doctor to discuss this. The earlier the diagnosis, the sooner you can start managing the condition.

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Medical Reviewer: Karin Gepp, PsyD
Last Review Date: 2022 Jan 20
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