The diagnosis of attention deficit hyperactivity disorder (ADHD) is made clinically. A careful diagnostic interview begins with the gathering from caregivers of a comprehensive picture of the child’s developmental status and symptoms. Information about the child’s functioning in different settings and contexts is essential, so the interviewer will understand where and in what situations symptoms occur. The intensity of symptoms in each setting must be ascertained.
In general, information is best obtained using a combination of open-ended and focused, semistructured questions. Symptoms may not be present in a structured setting, such as during an office visit, so observing the child in a classroom and on the playground can be useful.
Caregivers should be asked about the child’s:
Family and psychosocial histories provide information about how the family has handled the child’s difficulties and clarifies a family’s strengths and impediments in dealing with possible treatments.
A detailed medical history can help to exclude any physical causes that may account for symptoms. A physical examination should have been completed within the previous year. Routine laboratory screening, lead levels, and thyroid function tests are not indicated and should be performed only if warranted by a clinical evaluation.
The American Academy of Child and Adolescent Psychiatry, National Institutes of Health, and American Academy of Pediatrics have all published useful guidelines on the evaluation and diagnosis of ADHD.11–13
Behavior rating scales, long used in research, are well suited for both the initial assessment and the ongoing treatment of children with disruptive behaviors. Rating scales or checklists are helpful to the clinician in several areas:
Rating scales can either be broadband, covering a wide swath of psychopathology, or be designed to gather information about one disorder or group of symptoms. The Child Behavior Checklist (CBCL)14 is one of the most widely used general rating scales. It comes in various versions, to be completed by teachers, parents, preschoolers, and teenagers (in self-report form). The Revised Conners’ Rating Scales15 for parents and teachers is another scale that provides information in a number of symptom areas. Narrow scales used for the evaluation of disruptive behaviors include the short forms of the Conners’ Scales—the Conners’ ADHD/DSM-IV scales, global index, and ADHD index. The Swanson, Nolan, and Pelham Rating Scale (SNAP-IV) is keyed to the diagnostic criteria for ADHD and for oppositional defiant disorder (ODD), as cited in the DSM-II, DSM-IIIR, and DSM-IV.
These rating scales must be used appropriately. A youngster who meets certain cutoff points on any scale is not automatically considered to have the disorder in question. Likewise, a child who does not meet certain cutoff points may still have the disorder. These checklists should function in the same way that any laboratory test might be used: That is, they provide additional useful information but do not substitute for a careful diagnostic interview. In addition, discrepancies between different informants are not unexpected, and the interview process should seek to clarify those discrepancies.
A neuropsychological evaluation is a useful tool for evaluating a youngster for a learning disorder. The prolonged test session can sometimes reveal a variety of behaviors, including distractibility and hyperactivity, but the absence of these behaviors in this structured setting does not preclude the diagnosis. The freedom-from-distractibility factor on the Wechsler Intelligence Scale for Children III, which includes the arithmetic and digit span subscales, cannot discriminate between youngsters with and without ADHD.16 Other neuropsychological tests, including the Stroop Color Word Test and the Wisconsin Card Sort, which measure attentional functions, also do not successfully discriminate between youngsters with and without ADHD.
Continuous performance tests typically involve a 20-minute computerized task. Subjects need either to respond quickly or to inhibit a response to particular stimuli. Variables such as errors of commission, errors of omission, and response time measure attention, vigilance, and impulsivity. Although such tests are commercially available (e.g., Test of Variables of Attention, Gordon Diagnostic System), no evidence exists to prove that any are useful in making the diagnosis of ADHD or in consistently monitoring medication effects.
Reviewed and revised June 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.
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