What is ADHD?

tags: Center for Innovation and Leadership in Special Education Linking Research to Classrooms: A Blog for Educators

By Alison Pritchard, PhD
September 29, 2015

Most people today have heard of Attention Deficit Hyperactivity Disorder, or ADHD for short, but there is still a lot of misinformation out there on this topic. As a clinical psychologist who specializes in diagnosing and researching ADHD, I'd like to offer research-supported answers to some common questions about the disorder.

What is ADHD?

Attention Deficit/Hyperactivity Disorder (ADHD) is a brain-based condition common among children and adolescents. As the name suggests, there are two main categories of symptoms that fall under a diagnosis of ADHD:

  • Problems with attention
  • Problems with hyperactivity and impulsivity

The attentional difficulties can include trouble with focusing and holding attention on less preferred activities, hyperfocusing on more preferred activities, and trouble with organization and forgetfulness. These students may, for instance, forget to bring in homework assignments that they completed, start long-term projects the night before they are due, appear day-dreamy, or be unable to effectively take notes in class.

Hyperactivity can be physical ("bouncing off the walls", unable to sit still) and/or verbal (overly talkative); and impulsivity can be reflected in behaviors like interrupting, starting a worksheet before hearing the instructions, or doing things without thinking about the consequences. You may see students with ADHD classified as “predominantly inattentive,” “predominantly hyperactive/impulsive,” or “combined.” These classifications depend on the number and type of symptoms that a child demonstrates (APA, 2013).

What are some symptoms of ADHD?

In order to be diagnosed with ADHD – predominantly inattentive presentation, a child would have to show at least six of the following symptoms:

  • Making careless mistakes
  • Having trouble staying focused on a task
  • Having trouble listening
  • Having trouble with organization and/or time management
  • Getting easily sidetracked, not following through
  • Avoiding tasks that require sustained mental effort
  • Losing things often
  • Forgetting things often
  • Being easily distracted
  • Often fidgeting
  • Having trouble staying seated (e.g., in class, at the dinner table)
  • Often running or climbing when not appropriate, feeling restless
  • Having trouble playing quietly
  • Being often “on the go”
  • Talking excessively
  • Blurting out answers before the question is completed
  • Having trouble waiting his/her turn
  • Interrupting or intruding on others

The ADHD combined presentation diagnosis is reserved for youth who have at least 6 symptoms of inattention (the first group of bullets) AND at least six symptoms of hyperactivity/impulsivity (the second group of bullets). The predominantly inattentive presentation is roughly twice as common as either of the other types of ADHD (Froehlich et al., 2007; Merikangas et al., 2010).

Who has ADHD?

One out of every 11 school-aged children has ADHD (Pastor et al., 2015), so teachers are likely to have several children with ADHD in their classrooms at any given time. Boys are more often diagnosed with ADHD than girls (Akinbami et al., 2011); however, girls with ADHD may be under-identified if they are less disruptive in the classroom and at home. ADHD can be diagnosed as early as preschool and can continue to cause problems throughout adulthood. While the symptoms of ADHD may change somewhat with development, most children do not "grow out of" ADHD in adolescence or adulthood (National Center for Health Statistics, 2011).

Wait a minute, my desk is a mess and I am always forgetting where I left my keys, but I've never been diagnosed with ADHD...

Right, most people experience some of these symptoms from time to time, but that does not mean that you have ADHD. For a child to receive an ADHD diagnosis, he or she must demonstrate several symptoms that have persisted over time and that are seen in multiple settings (e.g., both school and home).

Ok, but my 3-year-old nephew can't keep his toys organized and interrupts me ALL the time. Does he have ADHD?

Another important part of an ADHD diagnosis is that the child's symptoms have to be inconsistent with their stage of development. For instance, while we typically expect that preschoolers will be energetic and “on-the-go,” most children have developed the capacity to sit still for 20-30 minutes at a time by the end of elementary school. Thus, if a 4th grader continues to have trouble sitting at his desk throughout a lesson, this would be inappropriate for his developmental level and might constitute a symptom. Also, even if a child has symptoms that meet all of these criteria, if these symptoms are not interfering with their functioning, either academically, socially, or at home, then an ADHD diagnosis would not be made.

I teach high school, and it is very rare for me to have a student who can't sit still or who interrupts in class, so I must not have many students with ADHD in my classroom, right?

The types of symptoms that students demonstrate often change with age and are typically related to the demands of their environment. For example, as children grow into adolescence, symptoms like physical hyperactivity are likely to improve (DuPaul et al., 2015). However, symptoms related to organization, planning, and motivation may become more prominent since the demands for independent organization and planning increase considerably as children make the transitions to middle and high school.

What causes ADHD?

There is no single cause of ADHD, though both heredity and environment seem to play a role in its development. Children with a family history of ADHD are at considerably greater risk of developing the condition than those without a family history (Doyle et al., 2005). Certain pregnancy and birth complications (e.g., prematurity, low birth weight), also contribute to an increased risk for ADHD (Lindstrom et al., 2011; Pettersson et al., 2015). From studies that have used brain imaging techniques such as MRI, we also know that the brains of youth with ADHD look and function somewhat differently than the brains of typically developing youth (Pritchard et al., 2012).

Are there good ways to treat ADHD?

Although we don’t know exactly what causes ADHD in a given child, we do know how to treat it for most children. Both behaviourally-based strategies and treatment with stimulant medications (e.g., Ritalin, Adderall) are effective in reducing ADHD symptoms and functional impairment (The MTA Cooperative Group, 1999). Also, teaching students to use accommodations such as extended time and graphic organizers, as well as positive behavioural and executive function supports in the school setting, can also be helpful for youth with ADHD (Hart et al., 2011). While ADHD often represents a significant challenge for affected youth, with appropriate treatment, support, and educational programming, these children can be successful in school and in life.

About the Author:

Alison Pritchard, Ph.D., is a licensed clinical psychologist who evaluates children with ADHD and related learning and behavioural concerns in the Executive Function Clinic within the Kennedy Krieger Institute's Neuropsychology Department.

Dr. Pritchard is also an assistant professor of psychiatry and behavioural sciences at the Johns Hopkins University School of Medicine and serves as the program director for the Kennedy Krieger Institute's Neuropsychology Research Lab.


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