With the completion of innumerable ADHD evaluations over the course of my professional career, I have finally arrived at the following important insight: not all ADHD is alike. On the surface, this statement may not initially appear to be quite so enlightening or profound. Yet it does reflect a personal recognition of the variation in symptoms that are often observed in the diagnosed ADHD child. Of course, the DSM-IV provides an ADHD symptom trait checklist to assist clinicians in making the diagnosis. My personal difficulty with this description of the disorder lies in the variability of the commonly observed symptoms that are used to diagnose ADHD.

Not all ADHD is the same. DSM-IV provides three different subcategories that are meant to illustrate the different possible presentations that are all recognized as ADHD. Unfortunately, there is a glaring absence of qualifiers in the checklist that describe severity, degree, and pervasiveness of symptom traits. Misinterpretation and misdiagnosis are frequent outcomes as a result of the clinical judgment that must be exercised by the evaluating professional.

So then how do we reasonably distinguish "normal" impaired attention from that recognized as a prominent dysfunction? If attention normally varies from person to person in the general population, how is it possible to identify when a child or adult is truly neurologically impaired? The best available answer to this dilemma would be the amount of developmentally inappropriate levels of inattention, hyperactivity, and impulsivity impairing one or more important life areas. Unfortunately, this guiding benchmark tends to rely on a diagnostician's clinical experience and judgment rather than an objective measure of symptom traits.

As I continue in my efforts to evaluate children for ADHD, I have come to realize the differences more than the similarities of those children who I have diagnosed with the condition. Hyperactivity and under regulated physical energy tend to be my most compelling symptoms to support an ADHD diagnostic. However, there have been occasions when I have experienced diagnostic ambivalence as when I observed a hyperactive child who was still able to focus his attention for reasonable intervals with a concerted effort. Another unusual example was observed in a truly hyperactive child who was easily able to stop all excess movement and activity in order to cooperate with a 20 minute individual interview. A final atypical example of ADHD symptoms occurred in the presentation of an ADHD child who despite extreme visual distractibility and physical hyperactivity was still able to monitor and even participate with adult conversation during the parent interview.

These unusual presentations of ADHD children have provided me with invaluable diagnostic experience. I have come to accept that there is a variable range of ADHD symptoms that can substantially challenge even the most experienced of clinicians. More importantly, not all ADHD is the same. While there tends to be a grouping of typical symptoms that describe the condition with or without hyperactivity, one must still be prepared to recognize deviant presentations of disruptive symptoms that still must be recognized as actual ADHD.

Perhaps of even greater importance is the recognition of attention as a complex brain activity that is quite variable in its presentation from one person to the next. We all tend to have greater or lesser abilities to sustain attention to tasks dependent on time, circumstance, and activity. This ability to focus attention not only varies largely from individual to individual, but is likely to vary within each individual as they progress through life. This suggests that most everyone will occasionally demonstrate similar amounts of inattention and distractibility experienced with enough intensity and duration to correspond with an ADHD diagnosis. These recognitions can encourage us to look more closely at the exact nature of ADHD as offered by the DSM-IV. Although some children and adults are accurately identified by ADHD, the fact remains that problems with inattention and distractibility are a commonality of experience in the general population. From my point of view, the challenge to identify ADHD in children must incorporate a range of factors and considerations that occasionally fail to be well represented in the symptom trait checklist for the disorder.