ADHD Guide

What Is ADHD? Symptoms, Subtypes & Treatments

ADHD (attention deficit hyperactivity disorder) is a neurological disorder that impacts the parts of the brain that help us plan, focus on, and execute tasks. ADHD symptoms vary by sub-type — inattentive, hyperactive, or combined — and are often more difficult to diagnose in girls and adults. Here, we review the symptoms, causes, types, and tests associated with ADD and ADHD.

What Is ADHD? Symptoms & Meaning

ADHD (attention deficit hyperactivity disorder) is a complex brain disorder that impacts approximately 11% of children and almost 5% of adults in the U.S.1 ADHD is a developmental impairment of the brain’s executive functions. People with ADHD have trouble with impulse-control, focusing, and organization.

Neuroscience, brain imaging, and clinical research tell us a few important things: ADHD is not a behavior disorder. ADHD is not a mental illness. ADHD is not a specific learning disability. ADHD is, instead, a developmental impairment of the brain’s self-management system. Both adults and children can be diagnosed with ADHD.

ADHD Symptoms

What are the signs of being ADHD? Common ADHD symptoms include:

ADHD symptoms vary by individual. You or your child may experience all or just some of the above symptoms, along with others detailed in the DSM-V.

[ADHD Directory: Find an ADHD Specialist or Clinic Near You]

Many patients and clinicians describe ADHD as an iceberg, where most symptoms lay hiding under the surface — out of sight but ever present. If you think you or a loved one might have ADHD, take one of our free, anonymous tests below to see if you should seek a formal diagnosis.

What Are the 3 Types of ADHD?

The Diagnostic and Statistical Manual of Mental Disorders (DSM)2 previously identified three types of ADHD:

  • Primarily hyperactive-impulsive type
  • Primarily inattentive type (formerly called ADD)
  • Primarily combined type

Primarily Hyperactive-Impulsive ADHD

People with primarily hyperactive-impulsive ADHD act “as if driven by a motor” with little impulse control — moving, squirming, and talking at even the most inappropriate times. They are impulsive, impatient, and interrupt others.

Primarily Inattentive ADHD (Formerly ADD)

People with the inattentive subtype of ADHD have difficulty focusing, finishing tasks, and following instructions. They are easily distracted and forgetful. They may be daydreamers who lose track of homework, cell phones, and conversations with regularity.

Experts believe that many children with the inattentive subtype of ADHD may go undiagnosed because they do not tend to disrupt the learning environment.

[Free Download: An In-Depth Guide to Inattentive ADHD]

Primarily Combined Type ADHD

Individuals with combined-type ADHD display a mixture of all the symptoms outlined above. A physician will diagnose patients with this Combined Type ADHD, of they meet the guidelines for Primarily Inattentive ADHD and Primarily Hyperactive-Impulsive ADHD. That is, they must exhibit 6 of the 9 symptoms identified for each sub-type.

How Do Physicians Diagnose the Type of ADHD?

These subtypes are now considered “presentations” in the most recent version of the DSM, the DSM-V. Researchers determined that people often move from one subtype to another. For example, a child may present as primarily hyperactive-impulsive in preschool, and  lose much of the hyperarousal in adolescence to fit the primarily inattentive presentation. In college and adulthood, the same individual may transition to combined presentation.

The subtypes were primarily based on overt behavioral symptoms, and ignored less visible symptoms like emotional dysregulation, cognitive patterns, and sleep difficulties. Behavioral symptoms imperfectly capture the defining features of ADHD. Non-behavioral characteristics are increasingly recognized in research and diagnosis.

What Are the Symptoms of Each ADHD Subtype?

The symptoms of ADHD are spelled out in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), which lists nine symptoms that suggest ADHD–Primarily Inattentive and nine that suggest ADHD–Primarily Hyperactive/Impulsive. A child may be diagnosed with ADHD only if he or she exhibits at least six of nine symptoms from one of the lists below, and if the symptoms have been noticeable for at least six months in two or more settings — for example, at home and at school. What’s more, the symptoms must interfere with the child’s functioning or development, and at least some of the symptoms must have been apparent before age 123. Older teens and adults may need to consistently demonstrate just five of these symptoms in multiple settings.

What Are the 9 Symptoms of ADHD – Primarily Inattentive Type?

  • Often fails to give close attention to details or makes careless mistakes in schoolwork, at work, or during other activities (e.g., overlooks or misses details, work is inaccurate).
  • Often has difficulty sustaining attention in tasks or play activities (e.g., has difficulty remaining focused during lectures, conversations, or lengthy reading).
  • Often does not seem to listen when spoken to directly (e.g., mind seems elsewhere, even in the absence of any obvious distraction).
  • Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (e.g., starts tasks but quickly loses focus and is easily sidetracked).
  • Often has difficulty organizing tasks and activities (e.g., difficulty managing sequential tasks; difficulty keeping materials and belongings in order; messy, disorganized work; has poor time management; fails to meet deadlines).
  • Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (e.g., schoolwork or homework; for older adolescents and adults, preparing reports, completing forms, reviewing lengthy papers).
  • Often loses things necessary for tasks or activities (e.g., school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).
  • Is often easily distracted by extraneous stimuli (for older adolescents and adults, may include unrelated thoughts).
  • Is often forgetful in daily activities (e.g., doing chores, running errands; for older adolescents and adults, returning calls, paying bills, keeping appointments)
  • Take the Self-Test: Symptoms of Inattentive ADHD in Children
  • Take the Self-Test: Symptoms of Inattentive ADHD in Adults

What Are the 9 Symptoms of ADHD – Primarily Hyperactive-Impulsive Type?

  • Often fidgets with or taps hands or feet or squirms in seat.
  • Often leaves seat in situations when remaining seated is expected (e.g., leaves his or her place in the classroom, in the office or other workplace, or in other situations that require remaining in place).
  • Often runs about or climbs in situations where it is inappropriate. (Note: In adolescents or adults, may be limited to feeling restless.)
  • Often unable to play or engage in leisure activities quietly.
  • Is often “on the go,” acting as if “driven by a motor” (e.g., is unable to be or uncomfortable being still for extended time, as in restaurants, meetings; may be experienced by others as being restless or difficult to keep up with).
  • Often talks excessively.
  • Often blurts out an answer before a question has been completed (e.g., completes people’s sentences; cannot wait for turn in conversation).
  • Often has difficulty waiting his or her turn (e.g., while waiting in line).
  • Often interrupts or intrudes on others (e.g., butts into conversations, games, or activities; may start using other people’s things without asking or receiving permission; for adolescents and adults, may intrude into or take over what others are doing).”
  • Take the Self-Test: Symptoms of Hyperactive & Impulsive ADHD in Children
  • Take the Self-Test: Symptoms of Hyperactive & Impulsive ADHD in Adults

What Causes ADHD?

The causes of ADHD remain somewhat unclear. Research suggests that genetics and heredity play a large part in determining who gets ADHD.4 However, scientists are still investigating whether certain genes, especially ones linked to the neurotransmitter dopamine, play a defined role in developing ADHD.

Additional research suggests that exposure to certain chemicals may increase a child’s risk of having ADHD.5

ADHD is not caused by bad parenting, too much sugar, or too many video games. ADHD is a brain-based, biological disorder. Brain imaging studies and other research show many physiological differences in the brains of individuals with ADHD.6

How is ADHD Diagnosed?

There is no single test for ADHD. To make a diagnosis, your doctor will assess for any ADHD symptoms exhibited by you or your child in the past six months. They will also do a physical exam and review your medical history to rule out any other medical or psychiatric conditions that could be causing symptoms.

Your doctor or specialists will perform an assessment using the Diagnostic and Statistical Manual of Mental Disorders (DSM-V), which details the symptoms listed above.

ADHD Diagnosis in Children

A child may be diagnosed with ADHD only if he or she exhibits at least six of nine symptoms outlined in DSM-V, and if the symptoms have been noticeable for at least six months in two or more settings — for example, at home and at school. What’s more, the symptoms must interfere with the child’s functioning or development, and at least some of the symptoms must have been apparent before age 12. Most children with ADHD receive a diagnosis in elementary school.

When diagnosing a child, your doctor or specialist may also review school records and questionnaires completed by your child’s teacher and/or caretakers. They will likely talk with and observe your child, as well as conduct screening for learning disabilities. They will also rule out other conditions that share similar symptoms to ADHD.

ADHD Diagnosis in Adults

Older teens and adults may need to consistently demonstrate just five of these symptoms in multiple settings. For an adolescent or adult to receive a diagnosis of ADHD, the symptoms need to have been present before the age of 12. Symptoms must also not be better explained by another disorder.

ADHD in Children

According to the Centers for Disease Control and Prevention, 1 in 10 children between the age of 5 and 17 receive an ADHD diagnosis7, making ADHD one of the most common childhood neurodevelopmental disorders in the U.S.

The symptoms of ADHD are often identified at school, as many children with ADHD have difficulty succeeding in a classroom setting. While teachers cannot diagnose ADHD, they are often the first to suspect ADHD in children as the symptoms typically affect school performance or disrupt the rest of the class.

Many symptoms of ADHD can be typical childhood behaviors, so it can be difficult to know if a child is displaying ADHD symptoms. Children with primarily hyperactive-impulsive ADHD may initially be seen as disruptive or misbehaving, as they are often hyper, impulsive, and impatient, and may interrupt at inappropriate times.

Boys are more than twice as likely as girls to receive an ADHD diagnosis8, in part because ADHD is still wrongly considered a male disorder and because boys are more likely than girls to exhibit outward signs of hyperactivity.

Adult ADHD

ADHD is diagnosed in roughy 4.4% of the adult population in the U.S., although this figure is thought to be underreported, as up to 85% of children with ADHD are at risk for having the disorder as adults, and only 10.9% of adults with ADHD receive treatment.9

Untreated ADHD in adults can negatively impact many aspects of life, including work, relationships, and mental health. Symptoms such as trouble managing time, impatience, disorganization, forgetfulness, and mood swings can all cause problems for an individual not actively taking steps to manage their ADHD.

Adult ADHD seldom exists alone. Roughly 60% to 70% of adults with ADHD have a comorbid disorder 10, such as anxiety, mood disorder, or substance abuse. If you suspect you may have adult ADHD, consult with your doctor or mental health professional about diagnosis and treatment so you can improve your well-being and quality of life.

ADHD Treatment

The best treatment strategies for ADHD are multimodal ones — combinations of several different, complementary approaches that work together to reduce symptoms. For one person, this ideal combination may include ADHD medication, nutrition, exercise, and behavioral therapy. For another, it may mean taking ADHD supplements and vitamins, practicing mindfulness, and spending lots of time outdoors in nature. More and more, pediatric and adult patients are pairing stimulant medication with digital therapies like EndeavorRx, which is available by prescription for patients age 8 to 12, or pinpointed apps like EndeavorOTC, a new mobile video game designed to improve focus in adults with ADHD.

Finding the right ADHD treatments — and managing them — takes research, planning, organization, and persistence. Early on, talk with your child’s doctor about your options.

ADHD Medication

For children aged 6 and over or adults, medication may be an important part of the treatment plan. Finding the right medication to manage ADHD typically involves some trial and error but can lead to a significant reduction in symptoms.

The two main types of medication used to treat ADHD are stimulants and non-stimulants.

Central nervous system (CNS) stimulants, like Ritalin or Adderall, are the most prescribed ADHD medications. These ADHD medications work by increasing the amounts of the chemicals dopamine and norepinephrine in the brain, which help with focus. There are three categories of stimulant medications:

  • Short-acting (taken a few times a day)
  • Intermediate-acting (taken less often)
  • Long-acting (taken one a day)

If stimulants cause problematic side effects, or simply are not effective, your doctor may suggest trying a non-stimulant medication, like Strattera or Intuniv.

Non-stimulant ADHD medications are considered second-line or third-line treatments because the level of benefits and response rates are significantly lower. Meaning, stimulant medications are more effective at relieving symptoms for a larger percentage of people.

ADHD medications can have many benefits, as well as side effects. The decision to manage ADHD symptoms with medication can be a difficult one. Learn more about the risks and benefits of stimulants and non-stimulants, medication options, how to gauge effectiveness, and more.

What Is the Definition of ADHD?

“Attention deficit” is, some experts assert, a misleading name. “Attention deregulation” might be a more accurate description since most people with ADHD have more than enough attention — they just can’t harness it in the right direction at the right time with any consistency. And so individuals with ADHD hyperfocus and lose track of time, or misplace their keys, or blurt out an unrelated thought when their focus breaks free from its chains.

Understanding ADHD: Next Steps


1 “Data & Statistics.” Centers for Disease Control and Prevention. Ed. Center for Disease Control. Centers for Disease Control and Prevention, 14 Feb. 2017. Web. 14 Mar. 2017.
2 Association, American Psychiatric, ed. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. Washington: American Psychiatric, 2014.
3 Association, American Psychiatric, ed. Diagnostic and Statistical Manual of Mental Disorders: DSM-5. Washington: American Psychiatric, 2014.
4 Thapar, Anita, and Evangelia Stergiakouli. “An Overview on the Genetics of ADHD.” Xin li xue bao. Acta psychologica Sinica (Aug. 2008)
5 Philip J. Landrigan, Jordan Slutsky. Are Learning Disabilities Linked to Environmental Factors? Learning Disabilities Worldwide.
6 Dovey, Dana. “Doctors May Soon Be Able To Diagnose ADHD With An MRI Scan.” Medical Daily. IBT Media Inc., 30 Apr. 2014. Web. 14 Mar. 2017.
7 https://www.(d(.gov/nchs/fastats/adhd.htm
8 https://www.(d(.gov/nchs/fastats/adhd.htm
9 Kessler, R. C., Adler, L., Barkley, R., Biederman, J., Conners, C. K., Demler, O., Zaslavsky, A. M. (2006). The Prevalence and Correlates of Adult ADHD in the United States: Results from the National Comorbidity Survey Replication. American Journal of Psychiatry. 163, 716-723.
10 Donzelli, G., et al.”The Association between Lead and Attention-Deficit/Hyperactivity Disorder: A Systematic Review.” International Journal of Environmental Research and Public Health. January 2019, 16:3. doi: 10.3390/ijerph16030382