By Gary E. Dudley, Ph.D.
Licensed Clinical Psychologist #520
Attention Deficit/Hyperactivity Disorder (ADHD) refers to a complex pattern of neurologically based behaviors. According the World Health Organization, incidence is between 4 and 7 percent of the population. There is no laboratory test or specific procedure for making a definitive diagnosis and current approaches to diagnosis are largely subjective. Diagnoses are often made on the basis of a few behavioral rating questionnaires completed by persons who often have a biased interest in having the diagnosis rendered. The insurance industry routinely refuses to authorize appropriate diagnostic procedures with the argument that “this problem can be adequately diagnosed with behavior rating questionnaires.” However, prescribing information provides a different view. The common central nervous stimulants used to treat this problem contain the following stipulation: “Specific etiology of this syndrome is unknown, and there is no single diagnostic test. Adequate diagnosis requires the use of medical and special psychological, educational, and social resources. The diagnosis must be based upon a complete history and evaluation of the patient and not solely on the presence of the required number of DSM characteristics (Physician’s Desk Reference).” In this regard, the argument to diagnose the syndrome solely on the basis of subjective symptom reports is uninformed and scientist/practitioners who support this view are, at least negligent, and arguably engaged in unethical practice.
Good science demands that when no objective means are available to correctly diagnose a neurodevelopmental disorder (or any other pathology for that matter) multiple methods of assessment are necessary and must be undertaken. Multimethod assessment is paramount in the diagnosis of a neuropsychological/developmental disorder that will have life changing impact on the child so diagnosed. I have practiced clinical psychology for over 35 years. I was a neuropsychologist before neuropsychology was organized into a specialty discipline. I often get requests from the Department of Defense, all branches of the military, and other government agencies for information about persons I evaluated 10, 20, or 30 years ago. They request diagnosis and treatment information. In many cases, persons who received this diagnosis have been denied the benefit of a top security clearance because they were diagnosed with Attention Deficit/Hyperactivity Disorder in early/mid childhood. At present, persons who have been diagnosed with Attention Deficit/Hyperactivity Disorder and received medication are not welcomed into service in the United States military. Diagnostic certainty is important.
For reasons offered above, multimethod assessment is important and involves some version of the following process. My assessment involves taking a detailed developmental history, obtaining multiple behavioral ratings from persons who have a history of observing the patient in multiple settings, and obtaining objective data from cognitive behavioral measures which focus on the specific symptoms relevant to the diagnosis.
Developmentally, children with ADHD are more likely to have had prenatal, perinatal, and early childhood events and/or illnesses than non-ADHD children. Such factors as pre-natal exposure to alcohol, tobacco, drugs and neurotoxins correlate with subsequent diagnosis of ADHD. Perinatal trauma, premature delivery, low birth weight, and certain viral illnesses in infancy are also correlates of ADHD. Childhood illnesses involving high fevers, frequent episodes of otitis media, or closed head injuries also correlate. A detailed and probing developmental history is essential to clarify developmental factors in order to ferret out these important possible clues to accurate diagnosis.
A second method of assessment (in the case of a child) is a measure of adaptive behavioral functions. Here, the clinician interviews a parent or guardian to determine levels of development for communication, socialization, and everyday living or self-help skills. Children with ADHD often have difficulty developing routines and habits for everyday functioning. In the words of quite a few of my patients, “my child reinvents getting dressed every morning….and he always forgets something.” Thus, very often, in the case of the ADHD child, levels of development for socialization and self-help skills lag behind that of other aspects of development and behind average ages of development for children in general.
Behavioral rating data are quite important but not sufficient for diagnosis. The insurance industry often demands that diagnosis be made on the basis of behavioral ratings alone for the obvious economical advantage of avoiding more complex and comprehensive assessment methods. To add to the complexity, rater bias may be a factor in producing false positives. Parents who are often distraught over the behavioral challenges presented by their children, hope that a quick diagnosis and the resulting “magic pill” will reduce the stress of managing difficult youngsters. Similarly, teachers faced with unruly children, or children that prefer to do what they like as opposed to complying with the teacher’s desire for the child’s full attention may be unconsciously motivated to make biased reports or distort the severity of inattention or impulse control problems on behavioral rating inventories.
This brings us to the importance of objective neuropsychological tests as a fourth type of measurement important in the diagnostic process. Neurocognitive assessment involves multiple procedures that test various cognitive skills (functions that allow our brains to screen out extraneous stimuli, attend to, remember, process, and store information) and are an important source of information. Some of the tested functions are particularly demanding of close and focused mental attention. For example, someone tells you their phone number. Do you remember it? For how long? Could you say it backwards? Other functions are not at all sensitive to attention. For example, what does the word “aberration” mean or “Who was president of the United States during the Civil War? It should be obvious that an individual who is impaired in their capacity to sustain focused attention would do better on the latter types of tests than on the former. By evaluating the pattern of performance between the attention sensitive procedures and those that are not demanding of close attention, another clue to accurate diagnosis is garnered.
Finally, a neuropsychological test that demands close and sustained attention but, at the same time, is excruciatingly boring is administered. In this procedure, the patient sits before a computer to watch and listen for the number “1.” When the patient hears or sees the number “1” he is required to click the mouse one time. New stimuli are presented 1.9 seconds apart so close attention and sustained concentration are required. If the stimulus is the number “2” clicking the mouse is an error of commission. If the patient fails to click the mouse on the number “1” it is an error of omission and evidence of inattention. Errors of commission are indicative of impaired impulse control, while errors of omission are indicative if impaired attention.
Now, by bringing all of the information from the four sources together, the clinician is able to determine if the various data produce a convergence. Do the various data all suggest that the patient demonstrates impaired capacity for sustained auditory and/or visual attention? Does the developmental history contain correlates of ADHD? Is there impairment to adaptive behavioral functions? Are data from various behavioral rating questionnaires supportive of impaired attention and/or impulse control functions in multiple settings? Are data from objective neuropsychological tests supportive of impaired attention and/or impulse control functions? Non-convergent data must be explained in a way that renders those data less significant for specific reasons i.e. the patient has particularly strong number skills, has had unusual practice at a specific function involved, or has large experience playing computer games that makes scores on the computerized test procedures spuriously high.
The process described above demands that clinical judgment is used to render a diagnosis. Many life situations and types of psychopathology produce primary symptoms of inattention, distractibility, and poor impulse control. A child who has experienced the death of an important person may look distant and inattentive in the classroom. An anxious person will appear distractible and may act without sufficient reflection. An angry individual may under-control impulses although the poor impulse control is not related to an underlying neurodevelopmental anomaly. The diagnostic manual used to categorize mental and emotional disorders contains nearly two dozen diagnosable conditions where inattention, distractibility, and impulsive behavior are primary symptom expressions but are unrelated to ADHD. Knowing when it is not ADHD is the responsibility of a skilled clinician and should not be left to a single source of information that is likely to over diagnose because of the narrowness of its scope. The child’s future will be impacted by a diagnosis of a neurodevelopmental disorder. It is important to get it right.