I’m guessing that the children most likely to be diagnosed with ADHD in your office are the obvious ones: stir crazy after a bit of time in the waiting room, in trouble at school and bouncing off the walls at home, fidgety and impulsive even in your short interactions with them.
It is children with the other face of ADHD – technically diagnosed as ADHD, predominantly inattentive type – who may be silently impaired, flying below the radar in your office and even at school.
They’re so easy to miss, these quiet daydreamers: slow, distracted, and forgetful.
They are often diagnosed at older ages than children with ADHD predominantly characterized by hyperactivity and impulsivity, largely because their symptoms may make them easy to overlook at school.
They don’t get sent to the office, but may bring home report cards that seemingly fail to reflect their intelligence. Their work remains unfinished, and they seldom know the answer when the teacher calls on them in class. Yet if neuropsychological testing were performed, they would be likely to test in the normal range.
Increasing research seems to suggest that inattentive children may have an entirely separate diagnosis from those who better fit the official ADHD title, which incorporates “hyperactivity” – a feature they may not exhibit at all.
The likelihood of comorbid learning disorders is much higher in children with inattentive-type ADHD than with classically hyperactive children with ADHD – as high as 70% in some studies.
Among the third of children who “outgrow” ADHD, few are of the inattentive type, seeming to indicate that the underlying neuroprocessing deficits in these children are more fixed.
The differential diagnosis for inattentive-type ADHD is broad and complex, akin to headache. Within it are physical problems, some quite serious; social stresses; and a variety of closely linked disorders that may be present as well, or masquerading as ADHD.
It is the pediatrician’s role to consider each of these, and then refer a child with suspected inattentive-type ADHD for neuropsychological testing to sort out subtleties within the processing and cognitive realms.
I always like to begin with targeted hearing and vision screening because a child who can’t see the blackboard or hear the teacher is absolutely going to tune out.
Next is the possibility – although unlikely – of absence (petit mal) seizures, which can look like inattention and have been known to persist for months without being diagnosed.
Social preoccupation is the next major consideration on my list, and it is an important one. Maybe the child isn’t paying attention in school because she is thinking about her alcoholic father, depressed mother, sexual abuse, or consequences of misbehavior.
If such a scenario interferes with a child’s ability to pay attention and learn at school, it’s critically important and needs to be addressed.
In a similar vein, the child’s basic needs may need to be assessed in an environmental context. Is he getting enough sleep and enough to eat? Is life at home so chaotic that the quiet of a school classroom allows her to let her guard down and disengage?
Language issues – either the inability to understand English or a processing disorder – may complicate the diagnosis and may coexist with inattentive-type ADHD. If these are suspected, a referral to a speech and language specialist is critical.
Cognitive ability may need to be formally tested as well. Perhaps the child is not inattentive, but simply does not have the intelligence to keep up in school as the material grows ever more complex.
Far and away, the most common missed diagnosis and frequent bedfellow of inattentive-type ADHD is anxiety.
Indeed, although it feels like our practices are filled with children with ADHD, anxiety is a more common pediatric disorder. Anxiety is present in 12%-13% of the patients we see, compared with 4%-12% with ADHD.
Like inattentive-type ADHD, anxiety may present as an internalizing disorder, and therefore may not be obvious. Even children overwhelmed by fears and phobias may not share their distress with a parent, teacher, or you, but may be so preoccupied by them that little else is getting through.
Anxiety is heritable and highly treatable, but it may be interwoven with other disorders and difficult to tease out.
So it’s a chicken and egg diagnosis with inattentive-type ADHD, and you’re not off the hook until you’ve thoroughly considered both possibilities, separately and together.
When I see combined anxiety/ADHD, inattentive type, I might treat the ADHD first, simply because response to stimulants is quicker and may enable a more comprehensive approach to the child’s anxiety.
Keep in mind that medication management of ADHD children with predominantly inattentive type is somewhat different from the standard regimens for children with hyperactivity and impulsivity. The stimulant family is still often used first, but the most efficacious dose may be lower and trickier to spot, and initial choices should be the least anxiety-provoking medications. Some clinicians prefer with this population to try extended-release atomoxetine.
With these children, I always start low and go slow, getting frequent, objective feedback from parents and teachers to try to stop within a narrow window of maximum efficacy for inattention. If you’re not careful, you can zip past that window and push the child into an anxious place that will make it seem that the medication isn’t working at all.
Once properly diagnosed and well medicated, inattentive-type ADHD is a diagnosis that requires adjustment in a child’s environment: at school, at home, and during other activities. The diagnosis itself entitles a child to receive special accommodations at school, which might include a change of seats to the front of the class, very direct attention by the teacher (who may want to tap on the child’s desk while making an important point), and even a special teacher-student microphone and headset that allow the teacher’s voice to be broadcast directly into the child’s ears. (These are expensive devices, and although they are effective, may be socially stigmatizing.)
Parents and teachers need to be educated about the complex nature of the diagnosis and its treatment, which needs to address all three critical components of attention: capturing the child’s attention, sustaining attention, and being able to shift attention to the next necessary piece of information. Each of these abilities requires different neurocognitive steps and requires different parts of the brain.
In considering this complexity, it is obvious that experts other than ourselves may need to be enlisted to sort out an individual child’s weaknesses and to design appropriate interventions. It also speaks to why this disorder may not belong in a diagnosis with more straightforward hyperactivity and impulsivity, so much more easily diagnosed and treated within the realm of general pediatrics.
This column “Behavioral Consult,” regularly appears in Pediatric News. Dr. Howard is assistant professor of pediatrics at the Johns Hopkins University School of Medicine, Baltimore, and creator of CHADIS, the Child Health and Development Interactive System (www.CHADIS.com). To comment, e-mail Dr. Howard at pdnews@elsevier.com.
