Diagnosis of Attention-Deficit Hyperactivity Disorder

Attention-deficit/hyperactivity disorder affects people of all ages but is usually diagnosed during childhood or adolescence. There is no diagnostic laboratory test for ADHD.

A thorough medical examination is important to identify other conditions that may be responsible for symptoms or that coexist with ADHD and require treatment. Hearing and vision assessments should be included in the examination. The most important diagnostic tool is the clinical interview.

The American Psychiatric Association (APA) provides the diagnostic criteria for ADHD. Generally, 6 or more symptoms, some of which must be present before age 7, must cause significant impairment for 6 months. Impairment must be seen in two settings, such as home and school, or home and work. Finally, symptoms must not be caused by another condition.

Differential diagnosis is necessary to distinguish ADHD from other mental health disorders and medical conditions, such as the following:

Clinical Interview & ADHD Diagnosis

Clinical interview of a child involves evaluating signs and symptoms; family history; home environment; academic, social, and emotional functioning; and developmental level. A variety of evaluative rating scales and clinical tests may be administered to patients, parents, and teachers to help sort out the signs and symptoms of ADHD.

Psychological testing may be used in the diagnosis of ADHD. For instance, the continuous performance test (CPT) measures and evaluates a child's attention span and ability to maintain focus on a task. An intelligence quotient (IQ) test may indicate a learning disability. However, psychological testing alone cannot be the basis for diagnosis.

In children at least 5 years old, "soft signs" may appear early and suggest the presence of ADHD. Soft signs include the following:

  • Coordination difficulties
  • Impaired motor skills
  • Constant, involuntary movement of the eyes (nystagmus)
  • Visual-motor control problems (hand-eye coordination)

Evaluation of an adult can be difficult and involves obtaining a childhood academic and behavioral history—including educational, vocational, and personal difficulties—as well as an evaluation of signs and symptoms. Observations of a spouse or significant other and recollections of parents can be useful.

Many adults have coexisting conditions, such as the following:

  • Depression
  • Bipolar disorder
  • Anxiety disorder
  • Obsessive-compulsive disorder
  • Substance abuse
  • Migraine
  • Irritable bowel syndrome
  • Thyroid dysfunction

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Jan 2001

Last Modified: 27 Aug 2015