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What is ADHD?

Welcome to the PEAKS Clinic Blog! Our first series will focus on Attention-Deficit/Hyperactivity Disorder (ADHD). We will begin by answering the following question, “What is ADHD?” There are many ADHD controversies and misconceptions in the public, media, and medical/mental health communities. Before we begin to tackle these more controversial issues, we need a common definition or shared understanding of ADHD. This will provide the groundwork for subsequent postings on the causes of ADHD, ADHD overdiagnosis, comprehensive ADHD assessment, and evidence-based treatments for ADHD.


SO….What is ADHD?

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM 5; the authoritative source for the defining and classifying mental health issues), Attention-Deficit/Hyperactivity Disorder (ADHD) is characterized by persistent, pervasive, and developmentally inappropriate levels of inattention and/or hyperactivity-impulsivity which negatively impacts social, academic, or occupational functioning (APA, 2013).

WHOA…maybe that was too dense. For clarity, it is important to examine each piece of this definition to better understand the five diagnostic criteria for ADHD (note criteria have been reordered for ease of understanding – see Anastopoulos & Shelton, 2001).

First and foremost, to meet criterion for ADHD (or another mental health diagnosis) an individual must experience functional impairment. In other words, if a child or adult does not have marked academic, occupational and/or social difficulties then they would (and should) not qualify for an ADHD diagnosis. The term ADHD is often misused in society. ADHD is not the same as being inattentive or overactive. Instead, an ADHD diagnosis describes someone who is experiencing significant functional impairment (e.g., academic, occupational and social difficulties) as a result of their inattention and/or overactivity. The goal is for the person to better understand the nature of their struggles and identify ways to improve their life.

To meet the second criterion for ADHD, individuals must “often” display at least six out of nine symptoms of either inattention and/or hyperactivity-impulsivity. Note that adults must display at least five out of nine symptoms of either inattention or hyperactivity-impulsivity. For example, an inattentive symptom is “often forgetful in daily activities” and a hyperactive-impulsive symptom is “often talks excessively”.

Being (over)active, getting bored, forgetting things, and making impulsive decisions is part of being human. We all display symptoms of ADHD at one point or another but clearly this does not mean that everyone has ADHD. To meet the ADHD symptom criterion one must: 1) display enough ADHD symptoms; 2) the ADHD symptoms must be displayed frequently or “often”; 3) the symptoms must be persistent meaning that they do not wax and wane overtime; and 4) the symptoms must be directly impacting academic, occupational, and/or social difficulties. Since we all display symptoms of inattention or overactivity at one point or another, ADHD evaluations must carefully consider whether the degree of inattention and/or hyperactivity-impulsivity is considered much higher than is expected given ones age, gender, and developmental context.

Third, ADHD symptoms must be displayed in multiple contexts. If you are getting inattentive or restless while reading this blog it probably just means that the author needs to do a better job engaging his readers :). If a child or adult were having difficulty sustaining attention or sitting still in just one context, they would not meet criteria for ADHD. For example, if a college student is having difficulty paying attention in one or two classes but not in other areas of life, then ADHD would not be an appropriate diagnosis as the individual’s inattention would likely be explained by other factors (e.g., early morning class, student was taking Dr. Smith’s Research Methods in Psychology Class :), or student is thinking about the fifty things they would like to get done tonight).

Forth, ADHD is a neurodevelopmental disorder and we expect ADHD symptoms and related difficulties to be present during childhood. In fact, for an ADHD diagnosis to be given, multiple symptoms need to be present prior to age 12.

Fifth, before ADHD can be diagnosed, the ADHD symptoms cannot be better explained by another disorder. Individuals who present with other mental health difficulties like conduct disorder, mood disorders, anxiety disorders, personality disorders, psychotic disorders, and substance use disorders may also experience ADHD symptoms. For example, many individuals who struggle with depression will also experience symptoms of inattention, forgetfulness, and disorganization. If the ADHD symptoms only occur during depressive episodes then an ADHD diagnosis would not be warranted.

In conclusion, to be diagnosed with ADHD one must meet all five diagnostic criteria for the disorder. However, when many people think about ADHD, they think primarily about ADHD symptoms of inattention, hyperactivity, and impulsivity. Unfortunately, this can come at the cost of evaluating the other four diagnostic criteria which may lead to multiple unintended outcomes, including the over- and misdiagnosis of ADHD (this will be covered in future posting).


Frequently asked questions about ADHD’s definition and terminology?

How can individuals with inattention but not hyperactivity get the same diagnosis as individuals with hyperactivity but not inattention?

ADHD is a diagnosis that describes a range of different behavioral symptoms, namely inattention, hyperactivity and impulsivity. Individuals may meet diagnostic criteria for ADHD by having developmentally inappropriate levels of inattention and/or hyperactivity-impulsivity. Although many individuals with ADHD have high levels of both inattention and hyperactivity-impulsivity, many individuals also present with high levels of only one symptom dimension. To account for the different expressions of clinically significant ADHD symptoms there are three main ADHD subtypes.

  1. ADHD combined presentation (314.01) describes individuals that have high levels of both inattention and hyperactivity-impulsivity

  2. ADHD predominantly inattentive presentation (314.00) describes individuals that have high levels of inattention but not high levels of hyperactivity-impulsivity

  3. ADHD predominantly hyperactive/impulsive presentation (314.01) describes individuals that have significant hyperactivity-impulsivity but not inattention.

What is the difference between ADD and ADHD?

Currently, the medical/mental health care community uses the term ADHD as defined by the DSM-5. The term ADD was used to describe between 1980-1987 (see DSM-III). Nearly thirty years later, there have been important changes to the definition of ADHD which is reflective in the terminology. See this article for an extensive history on the ADHD diagnosis. Perhaps ADD is still used for ease of communication, brevity, or to show off ones knowledge of ADHD diagnostic history through the use of “throwback” or “retro” terminology :). Nowadays the term ADD is typically used to describe ADHD Predominantly Inattentive Type. My take is if the medical/mental health care community is going to change diagnostic labels then we need to do a better job of adapting to the newer terminology and educating the media/public on these changes.

How long do you think it took for book authors to use the term “Attention-Deficit/Hyperactivity Disorder” more frequently than “Attention Deficit Disorder”?

***Remember that in 1987 Attention Deficit Disorder (ADD) was renamed Attention Deficit Hyperactivity Disorder (ADHD).

Answer: 17 years. In 2004, Attention Deficit Hyperactivity Disorder (ADHD) was finally used more frequently than Attention Deficit Disorder (ADD). No wonder so many people are confused about the difference between ADHD and ADD!

Note. Graph created by Google ngram viewer.

How many people meet criteria for ADHD?

How many people meet criteria for ADHD? Prevalence estimates for ADHD vary by age and study. The DSM-5 indicates that approximately that 5% of children and adolescents and 2.5% of adults meet ADHD criteria. The youth rate cited by the DSM-5 is slightly lower than a more recent meta-analysis of 175 studies finding that 7.2% of youth meet criteria for ADHD. Regardless of which prevalence estimate you prefer, both estimates are below the 8.8% of youth that received a “current” diagnosis of ADHD in United States in 2011. In other words, data suggests that there is a problem with overdiagnosis of ADHD in the United States (we will cover this more in a future posting). Note that estimates provided are based on previous definitions of ADHD (DSM-III, DSM-III TR, DSM-IV and DSM-IV TR) and changes to ADHD in DSM-5 (e.g., increasing the age of onset from 7 years old to 12 years old) may result in slightly higher prevalence rates, particularly for adults (see Matte et al., 2015).

Is ADHD diagnosed more in males compared to females?

Yes. For every two boys with ADHD there is one girl (this ratio decreases to about 3 men for every 2 women in adulthood). Does this mean that ADHD is really just “boys being boys?” Or that the boys will “grow out of it?” Not exactly. The persistence of ADHD symptoms and related impairment appears equally likely in boys and girls (e.g., van Lieshou et al., 2016) and men and women (Cortese et al., 2016). The presentation of ADHD, however, does vary based on sex. Females are more likely to present with predominantly inattention whereas males are more likely to have greater hyperactive-impulsive symptom severity.

Ok so that is probably more than you wanted to know about “What is ADHD” but if I missed anything or if you have a question/comment feel free to add it below or email me at Next up in the ADHD blog mini-series we will address the following question “What Causes ADHD?”

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