How To Diagnose a Toddler with ADHD

Don’t all little kids have short attention spans?

How hard is it to diagnosis ADHD in preschoolers?
How hard is it to diagnosis ADHD in preschoolers?

Photograph by Jupiterimages.

The American Academy of Pediatrics on Sunday issued new guidelines that urge parents and doctors to be on the lookout for signs of attention deficit hyperactivity disorder in children as young as 4. Previous guidelines set the minimum age at six. Preschoolers aren’t particularly focused in general—so how could you tell if one had ADHD?

He would fidget, interrupt, and not play well with others. ADHD is two disorders combined into one. Some children suffer from the “predominantly inattentive” form of the disease, which means they can’t focus on schoolwork, don’t follow basic instructions, and lose things all the time. Four-year-olds, however, are more likely to be diagnosed with the “predominantly hyperactive, impulsive” variety. These kids are extra squirmy, and act “as if driven by a motor.” They also climb things at inappropriate times and answer questions before the interrogator is finished asking. They’re lousy play dates, because they have trouble sharing and waiting their turn. The disorder can present a safety risk—young children with ADHD sometimes bolt out into traffic.

Parents will notice that virtually all 4-year-olds exhibit some of these symptoms. Don’t worry—there’s more to the disorder than being squirmy and infuriating. Children must exhibit a majority of the symptoms persistently for at least six months, and the behavior must be excessive for their age. As with many psychiatric disorders, there’s also a functional kicker: The symptoms should be interfering with a child’s development before any psychiatrist will apply the ADHD label. So, if your child is a handful but meets all of her developmental milestones, don’t go asking her doctor for a methylphenidate prescription.

ADHD diagnostic methods are notoriously controversial for children of any age. Doctors have to rely on reports from parents with no experience recognizing symptoms, and the impressions of various teachers. (Few children exhibit ADHD symptoms in a doctor’s office.) There are several different questionnaires and scoring scales that require mothers and fathers to speculate on how often their child talks too much: Never, sometimes, often, or very often. Doctors in the United States and abroad can’t even agree on a single definition of the disease.

Diagnosing 4-year-olds is especially problematic, because they may not have any teachers who could confirm the parents’ assessment. The formal diagnostic criteria also require that the child exhibit symptoms in more than one environment, but many 4-year-olds spend the overwhelming majority of their time at home. For this reason, the new guidelines urge parents to expose a problem child to a new environment like preschool or behavior therapy before turning to medication.

Unfortunately, there doesn’t seem to be a better way to diagnose the disorder. Several studies have suggested that some aspects of ADHD are heritable, but no one has been able to identify reliable genetic markers (PDF). Continuous performance tests are another option. Originally created to test radar operators, they require patients to respond to repeated stimuli. Subjects may, for example have to press the space bar whenever a letter other than x appears on a screen. Some research has suggested that ADHD sufferers have trouble with this test, but other studies have shown no difference between ADHD and normal patients, so the tests aren’t widely used. And, in any event, the test would be hard to adapt for 4-year-olds.

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Explainer thanks Michael Reiff of the University of Minnesota and Mark Wolraich of the University of Oklahoma College of Medicine.