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What is ADHD?

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common mental disorders affecting children. Symptoms of ADHD include inattention (not being able to keep focus), hyperactivity (excess movement that is not fitting to the setting) and impulsivity (hasty acts that occur in the moment without thought). ADHD is considered a chronic and debilitating disorder and is known to impact the individual in many aspects of their life including academic and professional achievements, interpersonal relationships, and daily functioning (Harpin, 2005). ADHD can lead to poor self-esteem and social function in children when not appropriately treated (Harpin et al., 2016). Adults with ADHD may experience poor self-worth, sensitivity towards criticism, and increased self-criticism possibly stemming from higher levels of criticism throughout life (Beaton, et al., 2022). Of note, ADHD presentation and assessment in adults differs; this page focuses on children.

An estimated 8.4% of children and 2.5% of adults have ADHD (Danielson, 2018; Simon, et al., 2009). ADHD is often first identified in school-aged children when it leads to disruption in the classroom or problems with schoolwork. It is more commonly diagnosed among boys than girls given differences in how the symptoms present. However, this does not mean that boys are more likely to have ADHD. Boys tend to present with hyperactivity and other externalizing symptoms whereas girls tend to have inactivity.

Symptoms and Diagnosis

Many children may have difficulties sitting still, waiting their turn, paying attention, being fidgety, and acting impulsively. However, children who meet diagnostic criteria for ADHD, differ in that their symptoms of hyperactivity, impulsivity, organization, and/or inattention are noticeably greater than expected for their age or developmental level. These symptoms lead to significant suffering and cause problems at home, at school or work, and in relationships. The observed symptoms are not the result of an individual being defiant or not being able to understand tasks or instructions.

There are three main types of ADHD:

  • Predominantly inattentive presentation.
  • Predominantly hyperactive/impulsive presentation.
  • Combined presentation.

A diagnosis is based on the presence of persistent symptoms that have occurred over a period of time and are noticeable over the past six months. While ADHD can be diagnosed at any age, this disorder begins in childhood. When considering the diagnosis, the symptoms must be present before the individual is 12 years old and must have caused difficulties in more than one setting. For instance, the symptoms can not only occur at home.

Inattentive type

Inattentive refers to challenges with staying on task, focusing, and organization. For a diagnosis of this type of ADHD, six (or five for individuals who are 17 years old or older) of the following symptoms occur frequently:

  • Doesn’t pay close attention to details or makes careless mistakes in school or job tasks.
  • Has problems staying focused on tasks or activities, such as during lectures, conversations or long reading.
  • Does not seem to listen when spoken to (i.e., seems to be elsewhere).
  • Does not follow through on instructions and doesn’t complete schoolwork, chores or job duties (may start tasks but quickly loses focus).
  • Has problems organizing tasks and work (for instance, does not manage time well; has messy, disorganized work; misses deadlines).
  • Avoids or dislikes tasks that require sustained mental effort, such as preparing reports and completing forms.
  • Often loses things needed for tasks or daily life, such as school papers, books, keys, wallet, cell phone and eyeglasses.
  • Is easily distracted.
  • Forgets daily tasks, such as doing chores and running errands. Older teens and adults may forget to return phone calls, pay bills and keep appointments.

Hyperactive/impulsive type

Hyperactivity refers to excessive movement such as fidgeting, excessive energy, not sitting still, and being talkative. Impulsivity refers to decisions or actions taken without thinking through the consequences. For a diagnosis of this type of ADHD, six (or five for individuals who are 17 years old or older) of the following symptoms occur frequently:

  • Fidgets with or taps hands or feet, or squirms in seat.
  • Not able to stay seated (in classroom, workplace).
  • Runs about or climbs where it is inappropriate.
  • Unable to play or do leisure activities quietly.
  • Always “on the go,” as if driven by a motor.
  • Talks too much.
  • Blurts out an answer before a question has been finished (for instance may finish people’s sentences, can’t wait to speak in conversations).
  • Has difficulty waiting for his or her turn, such as while waiting in line.
  • Interrupts or intrudes on others (for instance, cuts into conversations, games or activities, or starts using other people’s things without permission). Older teens and adults may take over what others are doing.

Combined type

This type of ADHD is diagnosed when both criteria for both inattentive and hyperactive/impulse types are met.

ADHD is typically diagnosed by mental health providers or primary care providers. A psychiatric evaluation will include a description of symptoms from the patient and caregivers, completion of scales and questionnaires by patient, caregivers and teachers, complete psychiatric and medical history, family history, and information regarding education, environment, and upbringing. It may also include a referral for medical evaluation to rule out other medical conditions.

It is important to note that several conditions can mimic ADHD such as learning disorders, mood disorders, anxiety, substance use, head injuries, thyroid conditions, and use of some medications such as steroids (Austerman, 2015). ADHD may also co-exist with other mental health conditions, such as oppositional defiant disorder or conduct disorder, anxiety disorders, and learning disorders (Austerman, 2015). Thus, a full psychiatric evaluation is very important. There are no specific blood tests or routine imaging for ADHD diagnosis. Sometimes, patients may be referred for additional psychological testing (such as neuropsychological or psychoeducational testing) or may undergo computer-based tests to assess the severity of symptoms.

The Causes of ADHD

Scientists have not yet identified the specific causes of ADHD. While there is growing evidence that genetics contribute to ADHD and several genes have been linked to the disorder, no specific gene or gene combination has been identified as the cause of the disorder. However, it is important to note that relatives of individuals with ADHD are often also affected. There is evidence of anatomical differences in the brains of children with ADHD in comparison to other children without the condition. For instance, children with ADHD have reduced grey and white brain matter volume and demonstrate different brain region activation during certain tasks (Pliszka, 2007). Further studies have indicated that the frontal lobes, caudate nucleus, and cerebellar vermis of the brain are affected in ADHD (Tripp & Wickens, 2009). Several non-genetic factors have also been linked to the disorder such as low birth weight, premature birth, exposure to toxins (alcohol, smoking, lead, etc.) during pregnancy, and extreme stress during pregnancy.


ADHD treatment usually encompasses a combination of therapy and medication intervention. In preschool-age and younger children, the recommended first-line approach includes behavioral strategies in the form of parent management training and school intervention. Parent-Child Interaction Therapy (PCIT) is an evidence-based therapy modality to help young children with ADHD and oppositional defiant disorder.

According to current guidelines, psychostimulants (amphetamines and methylphenidate) are first-line pharmacological treatments for the management of ADHD (Pliszka, 2007). In preschool-aged patients with ADHD, amphetamines are the only FDA-approved medication, although guidelines suggest that methylphenidate rather than amphetamines may be helpful if behavioral interventions prove insufficient. Alpha agonists (clonidine and guanfacine) and the selective norepinephrine reuptake inhibitor, atomoxetine, are the other FDA-approved options for treating ADHD. There are newer FDA-approved medications for ADHD treatment, including Jornay (methylphenidate extended-release) which is taken at night and starts the medication effect the next morning, Xelstrym (dextroamphetamine) which is an amphetamine patch, Qelbree (viloxazine) which is a non-stimulant, Adhansia (methylphenidate hydrochloride), Dyanavel (amphetamine extended-release oral suspension), Mydayis (mixed salts amphetamine product), and Cotempla (methylphenidate extended-release orally disintegrating tablets).

Many children and families can alternate between various medication options depending on the efficacy of treatment and tolerability of the medication. The goal of treatment is to improve symptoms to restore functioning at home and at school.

ADHD and School-Aged Children

Teachers and school staff can provide parents and doctors with information to help evaluate behavior and learning problems and can assist with behavioral training. However, school staff cannot diagnose ADHD, make decisions about treatment or require that a student take medication to attend school. Only parents and guardians can make those decisions with the child’s health care clinician.

Students whose ADHD impairs their learning may qualify for special education under the Individuals with Disabilities Education Act or for a Section 504 plan (for children who do not require special education) under the Rehabilitation Act of 1973. Children with ADHD can benefit from study skills instruction, changes to the classroom setup, alternative teaching techniques and a modified curriculum.

ADHD and Adults

Many children diagnosed with ADHD will continue to meet criteria for the disorder later in life and may show impairments requiring ongoing treatment (Pliszka, 2007). However, sometimes a diagnosis of ADHD is missed during childhood. Many adults with ADHD do not realize they have the disorder. A comprehensive evaluation typically includes a review of past and current symptoms, a medical exam and history, and use of adult rating scales or checklists. Adults with ADHD are treated with medication, psychotherapy or a combination. Behavior management strategies, such as ways to minimize distractions and increase structure and organization, and support from immediate family members can also be helpful.

ADHD is a protected disability under the Rehabilitation Act of 1973 and the Americans with Disabilities Act (ADA). This means that institutions receiving federal funding cannot discriminate against those with disabilities. Individuals whose symptoms of ADHD cause impairment in the work setting may qualify for reasonable work accommodations under ADA.

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Physician Review

Rana Elmaghraby, M.D.

Stephanie Garayalde, M.D.

June 2022

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