Module 10 – Attention-Deficit Hyperactivity Disorder

3rd edition as of August 2022

Module Overview

In Module 10, we will discuss matters related to attention deficit/hyperactivity disorder, commonly referred to as ADHD, to include its clinical presentation, prevalence, comorbidity, etiology, assessment, and treatment options. Be sure you refer to Modules 1-3 for explanations of key terms (Module 1), an overview of the various models to explain psychopathology (Module 2), and descriptions of the various therapies (Module 3).

Module Outline

• 10.1. Clinical Presentation
• 10.2. Prevalence and Comorbidity
• 10.3. Etiology
• 10.4. Assessment
• 10.5. Treatment

Module Learning Outcomes

• Describe how ADHD presents.
• Describe the prevalence and comorbidity of ADHD.
• Describe the etiology of ADHD.
• Describe how ADHD is assessed, diagnosed, and treated.
  

10.1. Clinical Presentation

Section Learning Objectives

• Provide a history of ADHD and clarify misconceptions.
• Describe common symptoms and associated features of ADHD.
• Outline the development and course of ADHD.

10.1.1. Brief Overview of the Recent History of ADHD

In previous editions of the DSM, a child could be diagnosed with either attention deficit disorder (ADD) or attention-deficit/hyperactivity disorder (ADHD). More recently, mental health practitioners have come to understand that both ADD, and ADHD are, in fact, the same phenomenon that simply present a little differently. ADD presents with more inattentive and distractibility symptoms whereas ADHD presents with more impulsive and hyperactive symptoms. While the symptoms seem different, mental health professionals realized they were related to a similar etiological and psychological phenomenon. Because of this, both disorders were combined into one disorder, ADHD, with specifications on the type: 1) Predominantly inattentive type, 2) Predominately hyperactive/impulsive type, and 3) Combined type. Since that time, we have come to understand ADHD even better, leading to a revision of the diagnostic criteria of the disorder.

With the publication of the DSM-5 (APA, 2013), and with its update, the DSM-5-TR (APA, 2022), the umbrella term ADHD was still used. However, instead of types, we now use the term “presentations.” This change occurred because it was realized that, although someone may exhibit more hyperactive/impulsive symptoms at one point in life (e.g., childhood), at a later point (e.g., adulthood), they may come to exhibit more inattentive/distractibility symptoms. With the use of types, the impression was that this change could not occur because the type was stagnant and stable. Use of the term presentations allows for a better understanding that symptom presentation can be fluid and change. Thus, we now have one disorder, ADHD, with three presentations (predominantly inattentive, predominantly hyperactive/impulsive, and combined). With some context now established in terms of how our understanding of attention-deficit/hyperactivity disorder has progressed over time, we now will examine its clinical presentation.

10.1.2. Clinical Presentation of Attention-Deficit/Hyperactivity Disorder

ADHD is a disorder in which individuals have difficulty with executive functioning, an individual’s decision-making ability, which involves working memory, inhibition of inappropriate or unhelpful responses, and the ability to focus on relevant information while dismissing unimportant or irrelevant information (Barkley, 2015). Essentially, an individual’s ability to regulate their cognitions, emotions, and behaviors, are impaired. Individuals may lose things frequently, talk excessively, forget assignments/appointments, fidget frequently, move constantly, get distracted, and struggle with organization. Symptoms also are required to be present in more than one setting. For example, if symptoms are only present at school, an individual would not be diagnosed with ADHD.

Symptoms are generally organized into two main categories: hyperactivity and impulsivity symptoms and inattention symptoms. An individual receives a diagnosis of ADHD with the needed specifier if there are: 1) at least six symptoms of inattention for this specifier, 2) at least six symptoms of hyperactivity and impulsivity for this specifier, or 3) six of each of the preceding two for the combined specifier (APA, 2022). The exact symptoms an individual may experience are described below.

     10.1.2.1. Inattentive symptoms (A1). Children who are inattentive tend to lose things necessary for tasks or activities, do not listen when spoken to directly, do not follow through on instructions and fail to finish tasks, do not give close attention to details or make careless mistakes, and are easily distracted by extraneous stimuli. They also are forgetful in daily activities; avoids, dislikes, or are reluctant to partake of activities requiring sustained mental effort; fail to sustain attention in tasks or play activities; and have problems organizing tasks and activities. Of these 9 symptoms, 6 or more must be displayed to receive the specifier and should have occurred for the past six months (APA, 2022).

     10.1.2.2. Hyperactivity and impulsivity symptoms (A2). These symptoms are related to excessive energy and movement as well as impulsivity. Individuals with these symptoms are often described as high energy or “on the go,” talkative, and fidgety. These children may have a hard time waiting their turn, standing still, remaining in their seat, or engaging in leisure activities quietly. They blurt out answers before the question has been completed and often interrupt or intrude on others. Of these 9 symptoms, 6 or more must be displayed to receive the specifier and should have occurred for the past six months (APA, 2022).

     10.1.2.3. Combined presentation. To receive the combined presentation specifier, an individual must display at least six inattention symptoms and six hyperactivity and impulsivity symptoms for the past six months (APA, 2022).

     10.1.2.4. Associated features. Individuals with ADHD (any specifier) display emotional dysregulation or emotional impulsivity, are often quick to anger, easily frustrated, and overreact emotionally. They may exhibit neurocognitive deficits and often show delays in language, motor, or social development.

     10.1.2.5. Development and course. Excessive motor activity is often observed by parents when the child is a toddler but, “…symptoms are difficult to distinguish from highly variable normative behavior before age 4 years” (APA, 2022, pg. 71). In preschool, hyperactivity is most common. ADHD is most often identified during the elementary school years as the inattention becomes more prominent and impairing. Hyperactivity becomes less prominent during adolescence and is confined to being fidgety, restless, or impatient. In adulthood, impulsivity, inattention, and restlessness may remain problematic, even if hyperactivity has diminished.

10.2. Prevalence and Comorbidity

Section Learning Objectives

• Describe the prevalence of ADHD.
• Describe common disorders that are comorbid with ADHD.
• Described disorders with similar presentations that must be differentiated from ADHD when diagnosing ADHD.

10.2.1. Prevalence of ADHD

ADHD occurs in about 7.2% of children worldwide, with cross-national prevalence rates ranging from 0.1% to 10.2% of children and adolescents and higher prevalence rates occurring in special populations, such as foster children and correctional settings. ADHD is more often diagnosed in males than in females. Females are more likely to present primarily with inattentive features. Because predominantly inattentive symptoms are not as disruptive and noticeable as hyperactive/impulsive symptoms, predominantly inattentive presentations of ADHD may go undiagnosed or be diagnosed much later than ADHD predominantly hyperactive/impulsive or combined presentations. Finally, ADHD is a risk factor for suicidal ideation and behavior in children (APA, 2022).

10.2.2. Comorbidity of ADHD

According to the CDC, approximately 60% of children with ADHD have another comorbid disorder (CDC, 2018a, September). About 50% of children with ADHD combined presentation, and about 25% of children with ADHD predominantly inattentive presentation, are also diagnosed with Oppositional Defiant Disorder (ODD). Conduct Disorder is also highly comorbid with ADHD (i.e., about 25% of youth with ADHD combined presentation) and most children and adolescents with disruptive mood dysregulation disorder have symptoms that also meet the criteria for ADHD (APA, 2022).

Learning disorders are also commonly comorbid with ADHD. However, differentiating if a learning disorder is present, in addition to ADHD, requires thorough evaluation (see differential discussion below).

Mood and anxiety disorders, as well as OCD and intermittent explosive disorder, are less likely to be comorbid than other behavioral disorders (CDC, 2018a, September). However, they do occur at a higher rate in children with ADHD compared to children without ADHD (APA, 2022). Many individuals with ADHD report daytime sleepiness that could meet criteria for hypersomnolence disorder.

10.2.3. Differential Diagnosis

     10.2.3.1. ODD. Because inattention and impulsivity can lead to noncompliance with rules, psychologists need to carefully assess behaviors and differentiate between ADHD and ODD. For example, a child may be told to clean their room. A child with ADHD may (1) not hear or fully attend to the instruction and then not comply or (2) may hear the instruction, begin to clean their room, get distracted mid-way, and start playing with a toy they found, perhaps impulsively, while they are supposed to be cleaning. Although noncompliant with the command, they are not actively being defiant. A child with ODD may be told to clean their room, and rather than comply, may actively defy the command. Because symptoms of ADHD can lead to a higher risk of noncompliance, we must be careful to not misperceive noncompliance with defiance. However, both can occur together (see comorbidity section above), and as such, when both are present, both will be diagnosed.

     10.2.3.2. Anxiety. Anxiety can lead to difficulty with concentration, fidgeting, and distractibility, which overlap with some symptoms of ADHD. It is not uncommon for a child to be referred for concerns related to ADHD, especially ADHD predominantly inattentive presentation, but may, in fact, be experiencing anxiety instead. Bear in mind that the inattention in anxiety disorders may be attributable to worry and rumination. Differential diagnosis of anxiety versus ADHD is important because treatment for the two disorders is different.

     10.2.3.3. Learning disorders. Because symptoms of ADHD can impair school performance and learning, psychologists must differentiate between (1) general impairment in learning due to inattentive, impulsiveness, etc. or (2) a specific impairment in an identified learning area (i.e., math, reading, written expression).

     10.2.3.4. Intermittent explosive disorder. Both disorders share high levels of impulsive behavior, but serious aggression toward others is common with intermittent explosive disorder and not ADHD. As well, those with intermittent explosive disorder do not experience issues with sustaining attention, characteristic of ADHD.

10.3. Etiology

Section Learning Objectives

• Describe biological bases/causes of ADHD.
• Describe environmental causes of ADHD.

10.3.1. Biological

     10.3.1.1. Genetic. ADHD is considered to be strongly influenced by genetics. Typically, ADHD has not been linked to chromosomal atypicalities. Rather, a general genetic susceptibility that has not fully been understood is at play. It is likely that ADHD susceptibility is polygeneic – involving more than one genetic trait. Twin studies have indicated that an average of 71-73% of ADHD symptom variance was explained by genetics factors (Barkley, 2015).

     10.3.1.2. Structural abnormalities. Physiological structural and functional abnormalities in the frontal lobe area of the brain have also been linked to ADHD symptoms. Some research indicates that other areas involved may include the anterior cingulate, basal ganglia, cerebellum, and corpus callosum. Additionally, smaller anterior right frontal regions, caudate nucleus and globus pallidus have also been associated with ADHD. Delayed maturation in the prefrontal cortex, which is also highly connected to executive functioning, has been associated with ADHD (Barkley, 2015).

     10.3.1.3. Functional differences. Slow wave activity in the frontal lobe and decreased beta activity has been noted in individuals with ADHD. Moreover, decreased blood flow in the prefrontal area of the brain have been indicated. Deficiencies in the availability of dopamine and norepinephrine (neurotransmitters) have been found in individuals with ADHD (Barkley, 2015).

10.3.2. Environmental

Very low birth weight is one of the strongest and most consistently noted environmental risk factors for ADHD, with more extreme low weight associated with greater risk (APA, 2022). Moreover, premature delivery is also associated with ADHD. Prenatal exposure to toxins, especially smoking, but also alcohol and other drugs, is associated with higher rates of ADHD. Additionally, environmental toxins, such as heavy exposure to lead or pesticides, is linked to ADHD symptoms (APA, 2022; Barkley, 2015).

Streptococcal infection has also been mildly linked to later development of ADHD. This typically only occurs when, following the infection, an individual’s body has an autoimmune response to the production of the infection antibodies that results in the destruction of the basal ganglia (Barkley, 2015).

In general, there is very weak evidence for psychosocial factors impacting the development of ADHD (Barkley, 2015).

10.4. Assessment

Section Learning Objectives

• Describe assessment tools commonly used.

When assessing for ADHD, psychologists often rely on parent-report, teacher-report, and observations. Occasionally, when the child is old enough, a psychologist will also incorporate the child’s own self-report of symptoms. To obtain parent and teacher reports (and when appropriate, self-report) of symptoms, a psychologist often utilizes two things: an interview and objective measures. For behavioral observations, a psychologist will often observe the child in person, either in their office and/or at school. A good assessment will include information from all three areas (i.e., observation, interview, and objective measures) to make an informed diagnostic decision. Unfortunately, there has been a growing issue in the field of children being quickly diagnosed based on a short, 15-minute visit with a pediatrician/primary care provider. This has led to a great deal of discussion about concerns of overinflated prevalence rates due to misdiagnosis. As such, there has been a big push in the field to have children properly assessed and diagnosed for ADHD, particularly before initiating medicinal intervention/psychopharmacology.

10.4.1. Observations

Observations can be completed in various ways. This is often determined by the setting in which an assessment is taking place as well as the resources available to a psychologist. For example, if the assessment is taking place within the school setting, a psychologist will often find a time to sit in a classroom with the child to observe him or her. The psychologist will attempt to do this with as little attention drawn to themselves as possible in an effort to observe the child without impacting their behavior. This is because children have typically been sent the message to “be on your best behavior” when a visitor comes to their classroom. As such, it is best that the teacher does not draw attention to the psychologist’s presence. This stage of the assessment often takes place before the child has ever met the psychologist as well. This is so the child is not aware that they are being observed. If the child were to meet the psychologist beforehand, the child would be more inclined to recognize that the psychologist was there for them and may attempt to monitor their own behavior. As such, the psychologist would not be able to obtain a valid observation of their behavior. (See Module 1, Section 1.5.2.1 about naturalistic observation for a more detailed discussion about the strengths and weaknesses of this research method.)

Although observation in a classroom or similar setting is ideal, this is not always feasible. This is more likely to be the case when an assessment is initiated in an outpatient setting (meaning a clinic, doctor’s office, etc.). School observations are difficult to obtain for professionals in the outpatient setting for various reasons. One reason is that managed health care (insurance companies) often do not cover services conducted within the school. This means that a psychologist working in a clinic cannot get paid for their time observing a child in a school. Other times, there is simply not an opportunity because a child is homeschooled, etc. In these circumstances, providers often rely on observing the child within the clinic. For example, some providers may intentionally wait to call a child from the waiting room for an appointment. Instead, they may use the first portion of their appointment to observe the child playing in the waiting room. Other times, they may simply conduct informal observations during their appointment. For example, while talking with parents, they may also be watching and noting various behaviors a child is engaging in. They may also spend time one-on-one with the child playing and talking. During this time, although it may seem like they are simply playing, the provider will be noting the various behaviors and interactions that are occurring. These are creative ways to obtain valid and important observations when sometimes more natural observations, such as a school observation, are not possible.

10.4.2. Interview

An assessment for ADHD should always include some version of an interview. This will likely start with a parent. The psychologist will sit with the parents and ask several questions. They will attempt to gain an understanding of when symptoms were first noticed, if the child is experiencing any impairment related to the symptoms, and so forth. While they will focus on understanding the presence or absence of ADHD-related symptoms, they will also screen for other potential disorders with common comorbidity and/or similar symptom presentations. For example, they may screen for ODD symptoms since it is commonly comorbid with ADHD. Moreover, they may also screen for anxiety symptoms since, often, anxiety and ADHD can present with similar symptoms and be misdiagnosed.

Because symptoms must be present in more than one setting, a secondary interview may be conducted. This often occurs with teachers. This is easily obtained in situations where an assessment is initiated in the school setting. However, in situations in which the assessment was initiated in an outpatient clinic, this is more difficult to obtain, even via phone. The reason for this is the same as outlined above in the difficulties with obtaining observations in outpatient assessments. As such, providers often rely on objective measures from a teacher if they are unable to obtain an interview. The focus of the teacher and parent interviews are often similar. However, in the teacher interview, the focus is more on specific impairment and functioning within the classroom and with peers. For example, the psychologist will ask many questions related to ability to stay on task, careless mistakes in work, ability to socialize with peers, etc.

If a child can communicate appropriately, meaning they are verbal and have appropriately developed speech, the child will be interviewed. This may occur informally while drawing or playing with the child, particularly if they are very young. As children get older, this will resemble more of an interview. Questions will focus on current difficulties such as “Is it hard to remember to turn your homework in?” “Do you lose things a lot?” “Do people say you talk a lot?” Again, these questions will be worded in a way that is appropriate for the child, depending on their age.

10.4.3. Objective Measures

There are a variety of objective measures that can be used. These are typically questionnaires that are filled out by the parent, teacher, and the child themselves (when appropriate). Children can begin reporting on their own symptoms anywhere between the ages of 6-11, depending on the specific questionnaire being used. Assessments specific to ADHD symptoms include, but are not limited to, the Conners-3, Disruptive Behavior Rating Scales (DBRS), and the NICHQ (National Institute for Children’s Health Quality) Vanderbilt Assessment Scales. The Conners-3 provides both overall scores as well as a symptom count. The DBRS and the Vanderbilt provide a symptom count number. Other questionnaires that may be used but are not specific for ADHD are the Behavior Assessment System for Children, Third Edition (BASC-3) and the Achenbach System of Empirically Based Assessment (ASEBA). These forms provide overall scores for scales related to hyperactivity, impulsivity, and inattention. However, they do not provide symptom counts. As such, the BASC and Achenbach scales are often used in combination with a tool such as the DBRS, Vanderbilt, and/or Conners-3.

10.5. Treatment

Section Learning Objectives

• Describe treatment options for ADHD.
• Examine efficacy of the varying treatment options.

Of children that are diagnosed with ADHD, about 30% are receiving medication only, 15% are receiving psychotherapy/behavioral therapy, 32% are receiving both medicine and psychotherapy/behavioral therapy, and 23% are receiving no treatment at all (CDC, 2018a, September). According to the CDC (2018a, September), 9 out of 10 children with ADHD receive some type of school support at some point in their education.

10.5.1. Psychopharmacological

     10.5.1.1. Stimulants. Historically, central nervous system (CNS) stimulants have been used the longest to treat ADHD, medicinally (CDC, 2018a, September). According to the CDC (2018b, September), 70-80% of children exhibit fewer symptoms with the introduction of stimulant medication. These medications work quickly and have short and extended-release formulas. This classification of drug includes methylphenidate and amphetamine. Stimulants are a controlled substance drug. These drugs work by increasing the availability of dopamine and norepinephrine (Barkley, 2015). Some negative side effects may include decreased appetite and resulting weight loss, difficulty sleeping, stomachaches and headaches, and higher heart rates/blood pressure. These drugs may potentially increase tics in children as well, if tics are a current concern (Barkley, 2015)

     10.5.1.2. Non-stimulants. These are considered a slightly newer generation of medicinal intervention for ADHD. These mediations do not typically work as quickly as stimulants, however, they may have longer lasting effects (CDC, 2018b, September). Because they are not a controlled substance, some parents prefer to attempt to alleviate symptoms using non-stimulant medications. Additionally, up to 30% of individuals may not respond, or only have a partial response, to stimulants (Barkley, 2015). As such, non-stimulants may be tried in lieu of stimulants or in addition to stimulants. Atomoxetine, guanfacine, and clonidine are examples of nonstimulants used for ADHD. Some negative side effects include headaches, decreased appetite, nausea/vomiting, sedation, and fatigue (Barkley, 2015).

10.5.2. Psychotherapy

Therapy to mediate symptoms of ADHD is typically behaviorally based. Therapies may be conducted with the child, parents, or both. Who the therapy is conducted with largely depends on the child’s age. For example, parent training is more likely to be utilized for younger and middle-aged children. However, older children and adolescents may also benefit from direct behavioral therapy. In some situations, a child/adolescent may benefit from receiving direct behavioral therapy while their parents also receive parent training (e.g., parent management training, PMT). At times, some work in cognitive and emotional realms may be beneficial as well. For example, children with ADHD are more likely to have a negative attribution bias. Essentially, they may interpret benign situations (e.g., someone accidently bumped into me) as hostile or malicious (e.g., they bumped into me on purpose) and then react impulsively to this. Cognitive therapy strategies can help to correct this misinterpretation of events.

     10.5.2.1. Parent training. The goal of parenting training is to help parents implement consistent parenting strategies to increase structure and predictability. For example, parents learn how to deliver instructions and commands to children in a way that they are more likely to be successful. This may mean breaking large chores down into more manageable pieces, etc. It also might focus on giving more attention and praise to positive behaviors while ignoring negative, minor misbehaviors. This is so that we see an increase in the behaviors we want to see (if we attend to a behavior, the behavior will increase because attention is a strong reinforcer) and a decrease in negative behaviors (when we ignore behavior, we remove attention which reduces the likelihood of it reoccurring since the strong reinforcer of attention has been withdrawn). There are various, evidenced-based and empirically supported, treatment protocols that target parent management training. Some examples include Incredible Years Parenting Program, Triple P, Parent-Child Interaction Therapy, Defiant Child, etc.

     10.5.2.2. Child-focused therapy. When working with the child or adolescent, we may begin working on implementing behavioral strategies to increase success and reduce impairment. While these are behaviorally focused, components of cognitive and emotional work may be intermixed to address common biases (see description of negative attribution bias above) and difficulties (e.g., low frustration tolerance). Also, because organization and studying skills are often impaired, another focus may be in Organizational Skills Training (OST). This training focuses increasing the child’s ability to organize materials, plan tasks, use checklists/timers/planners, and protect school and studying time (Gallagher, Abikoff, & Spira, 2014).

10.5.3. Academic Interventions

Children with ADHD may benefit from simple and common academic modifications. For example, because children with ADHD may be easily distracted, they may benefit from taking tests in an alternate location that is quiet and free from distractions. It is also likely that, because they are more prone to get off task or distracted, that it will take them longer to take a test. A common accommodation provided to reduce impairment in this area is offering extended time on tests. Other accommodations might include preferential seating (e.g., being able to sit in the front of the class where distractions are minimized and a teacher can prompt a child to be on task more readily) or alternative seating (e.g., ability to sit on a balance ball, quietly stand next to their chair rather than sit, etc.), and frequent breaks during assignments/tests. School-home notes and reward systems may also be implemented to (1) improve behavior in the classroom and (2) keep parents informed of the child’s behaviors as well as learning objectives and assignments due.

Module Recap

In this module, we learned about ADHD. We discussed the history of ADHD and how the field moved from two separate disorders (ADD and ADHD) to one disorder (ADHD) with three presentations (predominantly inattentive presentation, predominantly hyperactive/impulsive presentation, and combined presentation). We discussed the various behaviors and symptoms of ADHD and how they relate to the various presentations. We then discussed the prevalence of ADHD, disorders frequently comorbid with ADHD, and the etiology of ADHD. We ended on a discussion of how ADHD is assessed and treated.

In our next module, we will learn about oppositional defiant disorder (ODD) and conduct disorder (CD), two behavioral disorders.

3rd edition