Psychometric Testing for ADHD Diagnosis

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), the essential feature of ADHD is a persistent pattern of inattention and hyperactivity-impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development. However, as with any mental health problem, correct diagnosis is key. Inattention can be due to various factors, including understimulation, mood or anxiety disorders or oppositional behavior, so a proper assessment is crucial. Psychometric testing involves the measurement of a person's intelligence, knowledge, skills and other psychological aspects using valid and reliable tests.

Assessment Batteries

• A comprehensive assessment for ADHD will include several different tests designed to assess intelligence, achievement and memory, all factors that can affect performance. In addition, the clinician usually will obtain collateral data, such as a thorough history, grade transcripts and behavioral reports by parents, teachers and others who routinely observe the person. The clinician also may administer specialized tests to determine whether a learning disorder exists, as these problems are also present in 10 to 25 percent of individuals with ADHD.

Intelligence Tests

• When a clinician administers a test of cognitive ability, such as the Wechsler Intelligence Scale for Children (WISC) or the Wechsler Adult Intelligence Scale (WAIS-III), she is looking for a pattern of responses consistent with the criteria for ADHD. Both Wechsler tests measure verbal and performance abilities, which together form the combined score, often referred to as the "IQ" score. Some segments of these tests do not permit the test administrator to repeat instructions, which will affect the results when the patient suffers from an ability to focus his attention. This is taken into consideration when compared with other test results.

Achievement Tests

• The Woodcock-Johnson Tests of Achievement (WJ-III) is often used to assess actual performance in children and adults who may have ADHD. Although many individuals with attentional difficulties are actually quite intelligent, their achievement tends to lag because of these problems. Clinicians look for discrepancies between intelligence and achievement test scores that may indicate ADHD as well as high performance on tasks that do not require sustained concentration vs. poor performance on those that do.

Memory Tests

• Because memory constitutes an important part of learning, tests such as the Wechsler Memory Scales (WMS-III) may be used to determine whether the person is having difficulties processing and retrieving newly learned information. Attention is a necessary component in this process, and memory problems may reflect these attentional difficulties. Combined with poor performance, memory deficits provide additional support for a diagnosis of ADHD. Memory tests also can reveal strengths or weaknesses for visual or auditory presentation of information, which is helpful in constructing a treatment plan if ADHD is diagnosed.

Additional Assessment Tools

• Other instruments are available for more comprehensive ADHD assessment. For example, the Brown ADD Scales allows both the client and those who observe her behavior to rate the symptoms and problems she has experienced over the last six months. Personality inventories also may be administered to adult clients who are being assessed for ADHD, such as the Personality Assessment Inventory (PAI) or the MMPI (Minnesota Multiphasic Personality Inventory), to determine the presence or impact of other mental health disorders on functioning.