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Attention Deficit Hyperactivity Disorder or ADHD has become an increasingly popular label for people who seem restless and distractible, or have trouble remembering. Actually, there are many reasons for such behavior, and only some of them should correctly be labeled ADHD.
This chapter begins by describing ADHD. The next chapter addresses other conditions with some of the same symptoms that may be misdiagnosed as ADHD. It is important to keep in mind that thoughtful people sometimes disagree about how ADHD should be defined and treated. Thus, the content of this chapter represents both what most people agree are the appropriate statements about ADHD, as well as the author’s own judgment. Where consensus is lacking, the author will try to make that clear.

What is ADHD?

To begin, the name itself should be explained:

A = Attention

Defined as the mind’s ability to focus on what the senses are telling it as well as on what the person is thinking about at the same time.

  1. Most information people receive is through their eyes (visual reception) and ears (auditory reception); but people also take in information through their sense of touch, smell, taste, and intuition.
  2. As soon as information reaches the brain, the mind begins to interpret it, by relating what it is sensing to what it has experienced before.  This, for example, is how we know whether we are talking to a friend or a stranger on the phone; or whether someone is grilling hamburgers or vegetables; or whether the letter “a” is a small or upper case symbol.

In order to act on sensory information and the meaning one gives it, a person must also hold this information in mind while forming and executing a response. This aspect of attention is often called “working memory”—i.e., remembering something while “working” with it.

D = Deficit
Defined as a significantly reduced capacity to attend or focus, compared with the person’s general intelligence or demonstrated abilities in other areas.

H = Hyperactivity
Defined as unusual levels of motor activity and restlessness usually combined with impulsivity and failure to learn from mistakes, as well as anticipate consequences.

D = Disorder
Defined as persistent behavior (lasting more than 6 months) that undermines age-appropriate activity or interferes with normal life tasks.

Note that to date, the definition of ADHD has been developed to explain behavior in children and adolescents. Definitions of adult behavior in this area are subject to ongoing research and debate.

Primary Problems Recognized in Adult

Most people familiar with this disorder in adults agree that there are 3 primary areas of impaired functioning. Not all areas will be part of an individual’s experience with ADHD, and not all of the symptoms associated with an area will characterize that individual.

1. Executive Functioning
The brain’s executive functions are those that control behavior–including paying attention, managing emotional responses, and planning and carrying out goal-directed behavior.

Executive Functions Impaired in ADHD:

  • Thinking ahead—organizing, planning, anticipating consequences
  • Attention—concentrating, avoiding distraction, holding information in mind (Working Memory)
  • Self regulation—staying alert, sustaining effort, controlling impulsiveness
  • Emotion—managing frustration and modulating emotions
  • Mental flexibility—adapting to change
  • Self monitoring—observing and regulating actions

2. Working Memory
This area is related to executive functioning but deserves its own discussion. It requires the ability to concentrate, avoid distraction, and hold information in mind while applying it to a learning or problem-solving task.
Signs of Working Memory Impairment:

  • Forgetting instructions
  • Forgetting what is read from one sentence or paragraph to the next

3. “Secondary” Symptoms
These are problems that develop because of impaired executive and working memory functions; they include problems that often co-occur with ADHD symptoms.
Consequences of (1) and (2):

  • Chronic lateness and forgetfulness
  • Procrastination
  • Chronic boredom
  • Low frustration tolerance; anger
  • Relationship problems
  • Employment problems
  • Learning problems (with or without a corresponding learning disability)
  • Substance abuse or addiction
  • Anxiety
  • Low self-esteem, depression

General Considerations

With so many characteristics of ADHD to consider, it is easiest to think of it as which executive functions mature more slowly than expected. Oftentimes, a thorough diagnosis of ADHD in adults would include confirmation the individual showed symptoms in childhood.  ADHD is a lifelong condition and it is not something that arises suddenly.
ADHD is also a neurobiological disorder, which means it results from abnormal brain structure and/or chemistry. There are two explanations for its origin, and experts disagree on the proportion of persons with ADHD to assign to each source:

  1. ADHD may be found among several members and generations of families, indicating it is likely an inheritable condition. It also tends to occur with other disorders such as learning disabilities, alcoholism and depression, which suggests some individuals are born with a biological disadvantage.
  2. ADHD may be found among persons with no history of ADHD in the family.