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Diagnosis of ADHD

Is ADHD Real

adhd

Estimates vary, but the rates of ADHD fall between 3 to 5% (APA) and 7 to 12% (CDC) of children, with 60-85% continuing to meet criteria in adolescence, and 60% continuing to meet criteria in adulthood. Some authors debate whether ADHD is a real disorder, or simply a problem resulting from poor parenting, carbohydrate consumption and food additives, learning environment, etc…. ADHD is a “real” disorder, and many professional organizations have made clear statements to this effect:

  • In 1998, the American Medical Association stated that “ADHD is one of the best-researched disorders in medicine, and the overall data on its validity are far more compelling than for many medical conditions” (Goldman, 1998, as cited in Vaughan et al., 2012).
  • In 2007, the American Academy of Child and Adolescent Psychiatry said that while there is some debate about the best ways to identify and treat ADHD, “there is no debate among competent and well-informed health care professionals that ADHD is a valid neurobiological condition that causes significant impairment” (Pliskza, 2007, as cited in Vaughan et al., 2012).

Further, Vaughan et al. (2012) note:

  • Heritability estimates fall around 76%, meaning that when we study variations in hyperactivity and attention level, 76% of the differences we see among children comes from genetic factors. Studies have shown that when a child is diagnosed with ADHD, the parents and siblings of the child are two to eight times more likely to be or have been diagnosed with ADHD too.
  • Children with ADHD have smaller brain volume and smaller cerebral volume, and variations in the activity of the frontal-striatal cerebellar circuits (which connect the basal ganglia to the pre-frontal lobes). Other studies have shown that children and adolescents diagnosed with ADHD have higher rates of injuries (Lahey et al. 1998).

Thus, ADHD is a real disorder.

Diagnosis

There are three groups of patients with ADHD.

Children with ADHD

The diagnostic criteria for ADHD are written for children, and so are fairly clear to use. They require the child to have six symptoms of hyperactivity out of nine, or six symptoms of inattentiveness out of nine. These symptoms must have begun prior to age seven years. Nearly two thirds of children with ADHD also have another disorder. The MTA (study as cited in Vaughan et al., 2012) showed:

  • 31% of participants were diagnosed only with ADHD
  • 40% were diagnosed with ADHD as well as with Oppositional Defiant Disorder,
  • 35% were diagnosed with ADHD as well as with an anxiety/mood disorder
  • 14% were diagnosed with ADHD as well as with Conduct Disorder
  • 11% were diagnosed with ADHD as well as with a tic disorder

Preschoolers with ADHD

The diagnosis and treatment of preschoolers is more difficult. As noted, the diagnostic criteria are written for children, and so likely fit pre-schooler behavior. However, while they may show the same symptoms as older children, their symptoms may be the result of some delay in development. The child may “catch up” with peers in a year or so, and the “symptoms” disappear. Thus, the AACAP recommends a careful and thorough assessment and diagnostic process. When the diagnosis is given, providers may recommend that the parents seek treatment, may prescribe medications for six months and then re-evaluate after a discontinuation trial.

Adults and Adolescents with ADHD

Guidelines for ADHD are written for children, and so do not match adult symptom presentation very well (Manos, 2010):

  • For example, hyperactivity and impulsivity (as seen in children) are less likely in adults. These may be replaced with a restlessness or need to stay active, and be described as the ADHD adult is (or is seen by others as being) “driven by a motor”.
  • The ADHD adult may not be as “obviously” inattentive. When “fascinated” by an activity, they may have no problems, but when directed or effortful attention is needed, they may have difficulties. They may show poor time-management, and have difficulty remembering appointments and obligations as well as difficulty with starting and with completing tasks (these are items from the WHO Adult ADHD Self-Report Rating Scale, ASRS, Kessler et al., 2005).
  • They may also be more sensitive to (negatively affected by) stress and disorganization at work. This may result from changes that disrupt their coping strategies, or from concerns about their performance.

A large number of ADHD adults have a comorbid dx – commonly cited rates are below, though some studies have shown even higher rates (Manos, 2010):

  • 47% have an anxiety dx (think about being overactive and “fidgety”; changing moods and emotions, periods of high energy, and difficulty staying focused; intrusive worries about uncompleted work assignments and home-life responsibilities)
  • 38% have a mood dx (think about the problems with inattention and task completion noted above, or recurrent thoughts about mistakes and others’ criticisms)
  • 15% have a substance abuse dx (think about attention and organization difficulties, as well as broken agreements in social relationships)

Interviews with the adult; collateral interviews with coworkers, spouse, or friends; and rating scales can be useful in assessment (Manos, 2010).

  • Focus on recent changes in demands (family expectations, work duties, and other areas of life) that press the person to seek treatment.
  • Realize that ADHD does not have adult onset in our dx system, but the problems associated with ADHD may have an adult onset, especially as the adult works in less structured settings that require more effective self-direction.
  • Also assess compensatory strategies – some may be excessive (three hours at the end of the workday to get organized for the next day), and some may have been reasonable and effective (delegating some sedentary work tasks to others) before but are no longer effective after a change in demands (decreased support staff).
  • Kamradt et al. (2014) found that impulsivity and time-management difficulties (either reported by the patient or by peers) were especially good predictors of ADHD impairments in professional, personal, and work settings.

Neuropsychological tests can also help; however, they may not be diagnostic. Many studies have shown that there are significant and consistently observed cognitive deficits in adults with ADHD. Hervey et al. (2004) and Willcutt et al. (2005) conducted meta-analyses, reviewing a total of 116 studies, while Kamradt et al. (2014) collected their own data from almost 300 adults:

  • Difficulties in attention and vigilance – These refer to a person’s ability to attend to a task over time. These areas are sometimes assessed with continuous performance tests which require the person to engage in some task with simple instructions (for example, pressing the space bar when they see a number on the screen) and distractions (for example, presenting letters and shapes mixed in with the numbers) over time. The results show us errors of omission (the person failed to respond/press the space bar when they should have), as well as changes in reaction time (the person got better at the task with practice). Peer and self-evaluations of time-management skills can also be helpful in detecting problems in attention and vigilance.
  • Difficulty inhibiting responses, or impulsivity – The continuous performance tests noted above can also show us errors of commission (the person pressed the space bar when they should not have) which would reflect impulsivity in responding. Kamradt et al. (2014) found that impulsivity (as reported by either the patient or by peers) was one of two especially good predictors of impairments in professional, personal, and work settings.
  • Working memory – This refers to the “worksheet” in our minds. Imagine I asked you to figure out a math problem, or recall key details from a story I read to you. You might picture in your head a piece of paper where you could work out the math problem, or write down details of the story. This piece of paper would be your working memory. The results of such tests tell us how well the person can recall information (either on their own or with hints), and use it “on the spot” to make decisions.
  • Planning – This refers to problem analysis and solving, as well as set-shifting. This area is sometimes assessed with puzzles, mazes, or other tasks that require the person to figure out something by trial and error, or by alternating back and forth between different strategies.

Studies also show that there are other cognitive deficits which may be questionable; studies sometimes show these differences but sometimes do not. Kamradt et al. (2014) found that time-management difficulties (as reported by either the patient or by peers) was one of two especially good predictors of impairments in professional, personal, and work settings.

  • Processing speed – This refers to how quickly a person can evaluate information, make a decision, and act. Studies show ADHD adults are only slightly less able to respond quickly and accurately when the evaluation or action is simple. However, significant deficits appear when the evaluation and action become more complex, or must be done at the same time. If this seems too abstract, consider for example driving a car; adults with ADHD have long been shown to be at a greater risk for accidents (Barkley, 2004). Suppose there is some hazard, such as a piece of debris ahead in your lane. if you are a good driver, you must do many things in response:
    • First, you must attend to the road in front of you, and notice the debris (simple attention and concentration).
    • Next, you must decide whether you can safely drive over it (a risk to take), or must change lanes and avoid it (a single judgment). This decision is partly based on the driving conditions (an objective judgment), and partly based on accurate self-assessment of your driving skills (a reflective judgment).
    • Next, you must look to the left and behind you to assess the safety of changing lanes, while reassessing the time until you will hit the debris (more complex, as this is two judgments). Then you must assess your current speed, as well as the speed of the car now in the left lane, and determine that it is safe to change lanes (more complex, as this is three judgments simultaneously).
    • The time from noticing the debris to deciding how to react is your reaction time.
    • Next, you must remember to signal to warn another car that you will change lanes (or, judge that you must skip this step because there is not enough time to do so), then change lanes while you continually assess your distance from the upcoming debris, your control of your own car, and your distance from the car now behind you and from any car now in front of you (very complex, as it requires three judgments and two motor responses simultaneously).
    • If you judge wrongly, for example you change lanes and a drive blows a horn at you, then you must make new judgments and responses, such as swerving immediately back into your lane to avoid being rear-ended, and then bracing to hit the debris… or moving back into your lane just as you pass the debris. This requires multiple quick judgments and responses.
    • Of note, studies have shown that people with ADHD are
      • more likely to show variable reaction time (so may take longer to process all this information);
      • more likely to overestimate their ability and take risks (like deciding that it is safe to drive over the debris, or that they can switch lanes, avoid the debris, and switch back without disrupting the flow of traffic around them);
      • more likely to have accidents, have more expensive accidents, and report being at fault in the accident (consistent with failing to maintain attention, reacting too slowly, making poor judgments);
      • more likely to speed (reducing the time they had to react to changes in driving conditions);
      • more likely to struggle with rule-governed behavior and more likely to be rear-ended in an accident (consistent with following the rule to signal lane change to warn another driver, or with adjusting their speed so that they can change lanes without forcing others to slam on the brakes);
      • and more likely to “scrape” other cars and obstacles (which would reflect poorer fine motor control and visual judgment).
  • Executive functioning – This refers to decision making that requires more evaluation and consideration. This area is sometimes assessed with tests that require the person to engage in some tasks with complex rules, and so the person must consider several rules before choosing a response.
  • Intelligence – Intelligence tests assess a person’s abilities and knowledge in several areas. Typically, people with ADHD only show large deficits in those areas that rely on working memory (see above), but may show smaller deficits in other areas.

While tests of executive functioning, planning, and vigilance can identify ADHD in adults, only 30% of adult patients with ADHD score in the impaired range (Manos, 2010). Thus, diagnosing ADHD requires testing and interviewing (both the patient and those who work with/live with the patient).

References

Barkley, R. A., (2004). Driving impairments in teens and adults with attention-deficit/hyperactivity disorder. Psychiatry Clinica of North America, 27, 233–260.

Hervey, A. S., Epstein, J. N., & Curry, J. F. (2004). Neuropsychology of adults with Attention-Deficit/Hyperactivity Disorder: A meta-analytic review. Neuropsychology, 18(3), 485–503.

Kamradt, J. M., Ullsperger, J. M., & Nikolas, M. A., (2014). Executive function assessment and adult Attention-Deficit/Hyperactivity Disorder: Tasks versus ratings on the Barkley Deficits in Executive Functioning Scale. Psychological Assessment, 26(4), 1095–1105.

Kessler, R. C., Adler, L., Ames, M., Demler, O., Faraone, S., Hiripi, E., Howes, M. J., Jin, R., Secnik, K., Spencer, T., Ustun, T. B., & Walters, E. E. (2005). The World Health Organization adult ADHD self-report scale (ASRS): A short screening scale for use in the general population. Psychological Medicine, 35, 245-256.

Manos, M. J. (2010). Nuances of assessment and treatment of ADHD in adults: A guide for psychologists. Professional Psychology: Research and Practice, 41(6), 511–517.

Vaughan, B. S., March, J. S., & Kratochvil, C. J., (2012). Evidence-based pharmacotherapy of attention deficit hyperactivity disorder. In Dan Stein, Bernard Lerer, & Stephen Stahl (Eds.), Essential Evidence-Based Psychopharmacology (pp. 1-17). NY: Cambridge University Press.

Willcutt, E. G., Doyle, A. E., Nigg, J. T., Faraone, S. V., & Pennington, B. F. (2005). Validity of the executive function theory of Attention-Deficit/Hyperactivity Disorder: A meta-analytic review. Biological Psychiatry, 57, 1336–1346.