Diagnosis

The American Academy of Pediatrics issued its first guidelines for diagnosing attention-deficit hyperactivity disorder (ADHD) in children in 2002. They include the following:

• Children between ages 6 and 12 should first be evaluated for ADHD if they show symptoms of inattention, hyperactivity, impulsivity, academic underachievement, or behavior problems in at least two settings. Such behaviors should have been harmful for the child academically or socially for at least 6 months.
• The child should meet the official symptom guidelines.
• A diagnosis requires detailed reports by parents or caregivers. It should be noted that a mother's description of her child's behavior is a very accurate and reliable guide for diagnosing ADHD. Parents should not be shy about insisting on further evaluation if their experience does not match a doctor's single observation of their child.
• Guidelines for primary care doctors emphasize the importance of obtaining direct evidence from the classroom teacher or other school-based professionals about the child's symptoms and their duration, and evidence of functional impairment in the school setting.
• The child should be assessed for accompanying conditions (such as learning difficulties).

Difficulties in Identifying Children with ADHD

There are currently no laboratory or imaging tests to reliably diagnose ADHD. A diagnosis relies only on behavioral symptoms and ruling out other disorders. Many experts believe that the disorder is both over- and underdiagnosed. Diagnosis of attention-deficit hyperactivity disorder is difficult for some of the following reasons:

Arguments that ADHD is Overdiagnosed in Some Children.

• The popularity methylphenidate (Ritalin) has encouraged some parents and teachers to pressure doctors into prescribing this standard ADHD drug for children who are aggressive or who have poor grades. In one study of fifth graders in two different cities, 18% and 20% of Caucasian boys were being treated with medications. In one center, after careful testing, ADHD was the actual diagnosis in only 11% of children referred for ADHD, and 18% had no disability. Others were simply poorer learners or had no problems at all.
• In one study, children more likely to receive medication were young for their grade, indicating they may have been socially and intellectually immature, rather than behaviorally impaired.
• Being poor and growing up in a single parent household contribute to emotional and behavioral problems. The significant increase in these problems has also paralleled an increase in the diagnosis of ADHD children, who may simply be responding to social and economic problems.

Arguments that ADHD is Underdiagnosed in Some Children.

• Some evidence suggests that many girls with ADHD may go underdiagnosed. Research indicates that girls with ADHD are often inattentive but not hyperactive or impulsive. In fact, older girls with ADHD tend to have social problems due to withdrawal and internalized emotions, showing symptoms of anxiety and depression. The inattentive subtype, in any case, may first show up in older children and adolescents. However, according to the criteria, ADHD is not diagnosed in people whose symptoms appear after age seven.
• Doctors may fail to diagnose children with ADHD because they often behave normally in the quiet doctor's office where there are no distractions to trigger symptoms.
• In spite of the fact that there seems to be no differences in response to treatment among population groups, African American, Hispanic, and Asian children with ADHD are half as likely to be diagnosed and treated as Caucasian children. By high school, the racial disparity increases to the level that the medication rate for blacks is one-fifth of that for whites.
• ADHD may also be underdiagnosed in adults. Some experts, in fact, believe that ADHD may be the most common chronic undiagnosed psychiatric disorder in adults.

History of Behavior

The doctor will first require a detailed history of the child's behavior. Doctors will match this against a standardized checklist to define the disorder.

The parents should describe the following:

• Specific problems beginning as early as possible they have encountered during the child's development -- school reports are very helpful
• Sibling relationships
• Recent life changes
• A family history of ADHD
• Eating habits
• Sleep patterns
• Speech and language development
• Any problems during the mother's pregnancy or during delivery
• Any history of medical or physical problems, particularly allergies, chronic ear infections, and hearing difficulties

The health professional will want to know how the parents handle different situations, and may want to observe them interacting with the child.

Physical Examination

The child should also be given a general physical examination to determine if any medical conditions are present. The child should be given a hearing test to rule out hearing abnormalities as a source of behavioral problems.

Screening Tests

Continuous Performance Test. A test called the Continuous Performance Test is sometimes helpful in evaluating sustained attention and impulsivity. The child sits in front of a computer screen and is asked to press or not press certain keys in response to images on the screen.

Other Screening Tests. Other tests are available to test neurologic, intellectual, and emotional development problems. Most involve learning and problem solving tasks that help define the particular areas that are most disabling. Blood or other laboratory tests are currently recommended only if the doctor suspects lead toxicity or other medical problems.

Investigative Objective Tests

Optical Tracking and Attention Test. OPTax (optical tracking and attention test) uses two approaches:

• A test that measures the child's ability to be on task. According to a small study, untreated children with ADHD score 41.6% on average and children without ADHD score 82.4%. (Children who had been treated raised their scores to 75.4%.)
• A videotape that shows the child's head movements. Children with ADHD typically have movement characteristics that differ from children without ADHD.

Such a test offers a possible simple and objective way to determine a diagnosis.

QEEG Test. The quantitative electroencephalographic procedure (QEEG) assesses the electrical activity in a part of the brain called the prefrontal cortex. Evidence suggests that ADHD is associated with low activity in this region. Studies are reporting that it may be highly accurate in both diagnosing and ruling out ADHD in patients.

Imaging Techniques. Brain scans using imaging techniques, including magnetic resonance imaging (MRI) or single photon emission computed tomography (SPECT) may eventually help confirm a diagnosis. At this time, however, they are used only for research.

Drug Trials

Although it is fairly common to use a trial of a psychostimulant (usually Ritalin) to facilitate diagnosis, experts strongly recommend against this method of diagnosis, because it is not always accurate. An improvement in symptoms is considered suggestive of ADHD, while in non-ADHD children the stimulant often increases agitation and hyperactivity. Many children and adults without the disorder have a similar response, and such a diagnostic trial may lead to unnecessary prescriptions of this drug.