ADD vs ADHD: What are the Differences?

By Olivia Guy-Evans, published July 06, 2022 | Fact Checked by Saul Mcleod, PhD

Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders of childhood but is also prevalent in adulthood. ADHD is characterised by dysregulated attention and can have an impact on behaviours, emotions, and the ability to learn new things.

People with ADHD may seem restless, have trouble concentrating, and may act impulsively. The Centers for Disease Control and Prevention (CDC) suggest that about 9.4% of children and adolescents in the U.S have ADHD. 

The term attention deficit disorder (ADD) is now an outdated term and is no longer a diagnostic term in the Diagnostic and Statistical Manual of Mental Disorders (DSM), although it is often still used to refer to a subset of symptoms that fall under the umbrella of ADHD.

The term ADD first appeared in the third edition of the DSM, with experts separating the condition into two subtypes:

  • ADD with hyperactivity

  • ADD without hyperactivity

When the American Psychological Association (APA) released a revised edition of the DSM in 1987, they combined these two subtypes into one condition: ADHD. The latest version of the DSM (5th edition) divides ADHD into 3 types:

  • ADHD Predominantly Inattentive Presentation (what was previous known as ADD).

  • ADHD Predominantly Hyperactive-Impulsive Presentation

  • ADHD Combined Presentation (both Inattentive and Hyperactive-Impulsive symptoms). 

ADHD has had several name changes in the last few decades. This is because as more research is carried out, understanding grows and so the name has been changed to reflect that knowledge.

Is ADD the same as ADHD?

Some people may be frustrated that ADD is now known as ADHD. They can feel that the ‘H’, which stands for hyperactivity, does not accurately describe them or their child.

Often, when people hear the term ‘ADHD’, they may think of hyperactivity as being the main symptom, when a lot of the time, people with ADHD may not have this symptom.

It may be helpful for some people with ADHD to specify to others that they have inattentive ADHD, to clarify that inattention is their main symptom. 

Differences Between ADD (Inattentive ADHD) and ADHD?

Many may have used the terms ADD and ADHD interchangeably, but they are not the same. ADD refers to one particular type of ADHD – Predominantly Inattentive Type, whereas ADHD is the neurological disorder under which the Inattentive Type falls.

Since 1994, professionals have been using the term ADHD to describe both the Hyperactive-Impulsive and Inattentive subtypes of ADHD.

A key difference between ADD and ADHD is the element of hyperactivity. Those with ADHD are typically very energetic and may resemble more of the stereotypical behaviours that are thought of when considering ADHD, such as a child who cannot keep still and excessively climbs about.

They are thought of as being impulse individuals, may act out, and demonstrate behaviour problems. People with ADD however, often lack the hyperactivity component that is a prominent symptom of ADHD. 

ADD means that a person shows enough symptoms of inattention but is not thought to be hyperactive or impulsive. Those with ADD are considered to be daydreamers or appear disinterested and disorganised in the classroom or workplace.

They can be prone to forgetfulness, often losing items, and may struggle to follow instructions. Likewise, someone with ADD may be easily distracted, have problems sustaining attention on tasks, and may procrastinate on starting tasks that require considerable mental effort. 

ADD has been thought of as the ‘less severe’ form of ADHD. In reality, none of the types of ADHD are any more or less severe than the others.  The so-called ‘milder’ symptoms of ADD can still have a big impact on individuals.

The symptoms may not affect conduct or behaviour at school or work in obvious ways, but those with ADD may find that they still face plenty of difficulties focusing, staying organised, and completing tasks correctly or on time. 

Predominantly Inattentive ADHD (Formerly ADD)

Below are some of the common traits of those who have the Inattentive Type of ADHD:

  • Issues with paying attention on tasks which are difficult or boring

  • Poor working memory

  • Distractibility

  • Poor executive functioning

  • Poor focus

  • Low organisational skills 

  • Poor listening skills

  • Dislikes or avoids long mental tasks 

  • Trouble staying on task

  • May miss important details 

  • Loses things often

In children, the Inattentive Type of ADHD can be seen as the child being spacey and come across as apathetic behaviour, particularly in girls. In adults, Inattentive ADHD may resemble a mood disorder such as depression.

Those with this type may not focus on things that are not intrinsically interesting to them, especially for long periods of time. 

Diagnostic criteria for Predominantly Inattentive ADHD (Formerly ADD)

According to the DSM-5 criteria, at least six of the following symptoms must be present to warrant a diagnosis of ADHD, Predominantly Inattentive Type:

  • Often fails to give close attention to details or makes careless mistakes

  • Often have difficulty sustaining attention

  • Often does not seem to listen when spoken to

  • Often does not follow through on instructions and fails to finish projects

  • Often has difficulty organising tasks and activities 

  • Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort

  • Often loses things necessary for tasks/activities 

  • Is often easily distracted

  • Is often forgetful in daily activities

Hyperactive-Impulsive ADHD

The traits associated with the Hyperactive-Impulsive type align more closely with the stereotypical understanding of a ADHD:

  • A squirmy individual (usually in children)

  • Bursting with energy

  • Struggles to wait their turn

  • Talks excessively

  • Has nervous energy 

  • Taps and fidgets

  • Unable to engage in an activity quietly

  • A habit of finishing others’ sentences and interrupting others

  • Impulsive 

This subtype encompasses many of ADHD’s stereotypical traits and can be easier to spot in children as teachers and parents may have a hard time managing their behaviour.

In reality, a small portion of children and adults meet the symptom criteria for this type. 

What is hyperactivity?

When considering hyperactivity, people may often think of a child who cannot sit still and is very physically active.

As an adolescent or adult, hyperactivity may present in less obvious ways such as being talkative, over-working, or having many thoughts which jump from one topic to another. 

What is impulsivity?

Impulsivity in ADHD is seen as spur of the moment decisions without thinking about the consequences or long-term effects. Someone who is impulsive may:

  • Act quickly to get an immediate reward

  • Regularly interrupt others

  • Gamble or spend recklessly

  • Have emotional outbursts or find it hard to manage extreme or intense emotions

Diagnostic criteria for Predominantly Hyperactive-Impulsive Type

According to the DSM-5 criteria, at least six of the following symptoms must be present to warrant a diagnosis of ADHD, Predominantly Hyperactive-Impulsive Type:

  • Fidgets with hands or feet or squirms in seat

  • Leaves seat in classroom or in other situations in which remaining seated is expected 

  • Runs about or climbs excessively in situations in which it is inappropriate. Feelings of restlessness in teens and adults

  • Has difficulty playing or engaging in leisure activities quietly

  • Appears ‘on the go’ or acts as if ‘driven by a motor’

  • Talks excessively

  • Blurts out answers

  • Has difficulty waiting for their turn

  • Interrupts or intrudes on others

Trouble sustaining attention

A child with Inattentive ADHD may find it difficult to pay attention at school or they may have trouble focusing on activities or hobbies such as sports and games. An adult may struggle to maintain attention at work, in meetings, or during lengthy conversations.

They may even have trouble paying attention when doing things which interest them such as reading books. 

Problems with following instructions

Many children, adolescents and adults with Inattentive ADHD may struggle to follow through with instructions, fail to finish schoolwork, chores, or other workplace duties.

In many cases, it may be better for them to see the instructions written down or to be verbally told the steps one-by-one to help them follow through. 

Failing to listen

When spoken to directly, those with Inattentive ADHD may seem to be absent minded even without any distraction.

Adults may not listen when their partner or boss is speaking to them which can cause many issues. They may need others to repeat themselves multiple times before being able to comprehend what is being said to them. 

Making careless mistakes 

A child with Inattentive ADHD may rush through their homework or schoolwork, skipping over sections or giving incorrect answers due to not reading the questions properly.

As an adult, they may fail to carefully proofread a document or email at work which can lead to problems. Those with Inattentive ADHD may also make ‘social mistakes’ such as misinterpreting social cues which could lead to relationship issues.

Being unorganised 

Organisation can be challenging at any age for those with Inattentive ADHD. A child may struggle with keeping their room organised, an adolescent may find it hard to organise their study times, and adults can feel overwhelmed by work emails, with paying bills on time, and doing their taxes.

Poor organisation skills can often go together with unfinished work, poor time management, and a failure to stick to deadlines. 

Losing items

A child with Inattentive ADHD may always find that they lose their homework or school supplies whereas an adult may often misplace their phone or keys.

They may forget where they have placed items in a room, causing them to be late for school, work, or other events if they are spending extra time finding what they have lost. 


Since difficult tasks require a lot of attention and concentration, those with Inattentive ADHD may avoid these tasks as long as possible, often until the deadline is imminent.

They may often have difficulty completing projects, schoolwork, workplace tasks, essay assignments, and filling out forms. 

Easily distracted 

Children with Inattentive ADHD may become easily distracted by any environmental stimuli in the classroom, which is why they may often be labelled as a ‘daydreamer’.

Adults may drift off into their thoughts, switch rapidly from one topic to another, and lose focus on the task at hand. 


Those with Inattentive ADHD may forget to do their homework, forget appointments, important tasks, pay bills, return emails, and keep track of special dates such as birthdays and anniversaries.

They may even forget to perform tasks to take care of themselves such as eating and showering. 

Which Type of ADHD is More Common in Girls and Women?

ADHD has long been thought of as a condition that affects males due to the diagnostic criteria being based on hyperactive boys. More girls and women have gained a diagnosis as the understanding of ADHD has deepened.

It is believed that more women and girls are thought to have Inattentive ADHD than the Hyperactive-Impulsive presentation. Girls are more likely to have Inattentive ADHD, in which daydreaming, and shyness are common, whereas it is more typical for boys to have Hyperactive-Impulsive ADHD or the combined type. 

This is not to say that girls cannot also be hyperactive. It is suggested that a lot of girls present with hyperactivity in different ways – they may be chattier and more rebellious, but this may not be picked up as being anything out of the ordinary. 

Girls who struggle with inattentive issues are often overshadowed by hyperactive boys who are more likely to demonstrate more stereotypical hyperactive ADHD behaviour.

Girls and women are also more likely to mask their symptoms of ADHD. A reason for this may be that girls are often expected to be more social than boys and so they learn to present in ways which are deemed more acceptable, which can make it harder for girls to get a diagnosis. 

Often, girls and women who have undiagnosed ADHD get diagnosed as having a mood disorder. This may be because their undetected symptoms can lead to complications such as anxiety and depression, which can be flagged up more easily by professionals.

A lot of the time, girls and women do not seek help for their ADHD until they have developed comorbid conditions. 

How Does ADHD Present in Adults?

ADHD is often diagnosed in childhood and can persist into adulthood. The average age that someone receives a diagnosis of ADHD is around 7 years of age. It is thought that as many as 11% of school-aged children are believed to have ADHD.

The condition is often more diagnosed in males than female, to a ratio of approximately 3:1. According to the Diagnostic and Statistical Manual and Mental Disorders (DSM-5), symptoms of ADHD must have been prevalent prior to the age of 12 for a diagnosis to be made. 

ADHD can present differently in children and adults. In children, the symptoms of ADHD typically cause issues at school such as being disruptive, not being able to pay attention, difficulties concentrating on a task, and they may be unable to sit still for extended periods of time.

Likewise, children with ADHD may have a lower threshold for frustration, difficulty controlling their emotions, and they may experience mood swings. 

In adults with ADHD, the symptoms can change to some extent. The hyperactive symptoms can become less visible, finding they can relatively sit still, instead the hyperactivity can come from internal restlessness, such as rapid and changing thoughts and ideas.

The inattentive symptoms of ADHD usually remain consistent although adults can usually have somewhat more control over their environments than children do, so whilst children are expected to sit still at a desk most of the day, some adults can choose a job where they can move around more.

Whilst the symptoms may change as they become adults, ADHD can still interfere with an adult’s functioning, specifically in their work life, relationships, family life, and finances. 

ADHD is often thought of as a condition for children which they grow out of once they become adults. However, a 2021 review found that nearly 2.6% of the global adult population have persistent ADHD from childhood, while about 6.7% of adults have adult ADHD (Song et al., 2021). 

In some cases, ADHD is not recognised or diagnosed until the person reaches adulthood, with many people never being diagnosed. Many people may find that their symptoms improve with age, although if a diagnosis or treatment is missed, they may find that their symptoms continue to be difficult to cope with. 

Adult ADHD may not be as clear as ADHD symptoms in children. In adults, hyperactivity may decrease, but struggles with impulsiveness, restlessness, and difficulty paying attention may persist. Their hyperactivity may present in different ways such as being talkative, fidgety, and having nervous energy. 

Other symptoms which may persist into adulthood include trouble focusing on tasks, easily losing track of time, struggling with executive functions, and finding it hard to sustain attention for extended periods of time. 

Problems that adults with ADHD face

As an adult, there are usually more responsibilities such as caring for children, having a job, and managing a household. An adult with ADHD may find these tasks exceedingly difficult and it may lead to further problems.

In childhood ADHD, it might matter less if things are misplaced or forgotten, especially if the child has a family member to help them out. As an adult, forgetting to pay bills, being late with rent, and losing their wallet can have more serious consequences.

Adults with ADHD may also experience a lot of difficulties in relationships. If the person is not attending to their partner or friends, are constantly asking for repetition, and forgetting important events, this can put a strain on these relationships.

A romantic partner of an adult with ADHD may become frustrated that their partner never appears to listen to them, remember to do important household tasks, or pay them attention.

Finally, comorbid conditions are very common in adults with ADHD. It is thought that 80% of adults with ADHD have a comorbid condition including depression, anxiety, bipolar disorder, substance-use disorders, and personality disorders (Katzman et al., 2017).

Fact Checking

Content is rigorously reviewed by a team of qualified and experienced fact checkers. Fact checkers review articles for factual accuracy, relevance, and timeliness. We rely on the most current and reputable sources, which are cited in the text and listed at the bottom of each article. Content is fact checked after it has been edited and before publication.

About the Author

Olivia Guy-Evans obtained her undergraduate degree in Educational Psychology at Edge Hill University in 2015. She then received her master’s degree in Psychology of Education from the University of Bristol in 2019. Olivia has been working as a support worker for adults with learning disabilities in Bristol for the last four years.

Cite this Article (APA Style)

Guy-Evans, O. (2022, July 06. ADD vs ADHD: What are the Differences. Simply Psychology.


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