Attention-deficit/hyperactivity disorder is a concept that has been around for many years under different names (attention-deficit disorder with and without hyperactivity, minimal brain dysfunction, hyperkinetic disorder).
There are three myths about ADHD that make diagnosis confusing. First, is the myth that a positive clinical response to stimulants confirms the diagnosis. In fact, stimulants can improve the ability to focus in both ADHD and normal people. Second, is the myth that ADHD will be outgrown, and therefore it is a disorder of childhood. In fact, it seems clear that teenagers and adults with ADHD continue to benefit from stimulant medication, and long-term follow-up studies seem to indicate that a significant number of children with ADHD continue to have symptomatology of the disorder as adults (although research into the long-term effects of stimulants on the brain and the heart are severely limited). The third myth is that, if the child does not exhibit the signs of ADHD in the physician’s office, the child must not have ADHD. Because of the prevalence of these myths, the diagnosis has not even been considered in adults until recent years.
Other diagnostic problems include the frequent co-occurrence of ADHD with other disorders (this is called comorbidity), such as conduct disorder, mood disorders, bipolar disorder, and substance abuse, and the overlap of ADHD symptoms with those of other disorders.
It is helpful to think of attention regulation on a spectrum (table). The attention spectrum may range from impaired ability to sustain focus (excessive distractibility and attention to extraneous stimuli) on one end, to hyper-focusing (inadequate disengagement of attention, such as uncontrolled obsession and stereotypical ritualized behavior) on the other end. Given this model, I think of attention-deficit/hyperactivity disorder (ADHD), and obsessive-compulsive disorder (OCD) under the heading of “disorders of attention”. You should be aware, however, that DSM-IV classifies ADHD under “disorders usually diagnosed in infancy, childhood, or adolescence” and OCD under “anxiety disorders.” My presentation of these disorders under one heading of attention disorders is not meant as a substitute for DSM-IV or the new DSM V, merely as another way of conceptualizing these disorders that might have some clinical benefit and stimulate your thinking.
In this model, at the “underfocused” end of the spectrum, the purest form of an attention disorder is attention-deficit/hyperactivity disorder-predominantly inattentive type (ADHD-i). Currently classified under ADHD, and the syndrome which has been the primary focus of most research is attention-deficit/hyperactivity disorder-predominantly hyperactive-impulsive type (ADHD-h). In the model presented here, ADHD-h is ADHD-i with a significant additional component of motor hyperactivity and/or impulsivity, possibly related to differences in serotonin regulation (Halperin et al., 1994). The “hyperfocused” end of the attention spectrum is somewhat less consistent with DSM-IV.
Here, new subcategories of OCD are required, analogous to those in the current typology of ADHD. In this model OCD-predominantly obsessive type (OCD-o) would be the purest form of attention disorder at the “hyperfocused” end of the spectrum; when accompanied by motor impulsivity, the clinical picture would be OCD-predominantly compulsive type (OCD-c).
Just as some patients with mood disorders may be depressive only, while others are bipolar, so it may be with dysregulation of attention. Therefore, it is not uncommon to see some patients who exhibit states of both “underfocusing” or inattention (ADHD) and “hyperfocusing” or inability to shift focus (OCD). In fact, patients with tic-like OCD often have accompanying ADD, as do patients with Asperger’s syndrome (right hemisphere deficit disorder).
Hypothesized Model of Attention Disorders
|Ability to Sustain Attention||Clinical disorder with cognitive symptoms only||Clinical disorder with cognitive and motor symptoms (impulsivity)|
|Low||Attention deficit/ hyperactivity disorder-inattentive type (AD/HD-i)||Attention deficit hyperactivity disorder-hyperactive impulsive type (AD/HD-h)|
|High||Obsessive-compulsive disorder-obsessive type (OCD-o)||Obsessive-compulsive disorder-compulsive type (OCD-c)|
|Both||AD/HD-i and OCD-o||AD/HD-h and OCD-c|