Attention-deficit hyperactivity disorder (ADHD) is diagnosed through an individual’s behavioral symptoms. No medical, physical or genetic test exists. A complete diagnostic evaluation should include the following:
- Clinical interview
- Detailed history of the indentified patient’s difficulties
- Symptoms checklist
- Psychological tests
- Medical exam
- Additional testing (optional)
Clinical Interview An ADHD diagnosis begins with a clinical interview by a qualified mental health professional. During this interview, the identified patient will be assessed based on their adherence to the diagnostic criteria as outlined by either the American Psychological Association’s Diagnostic Statistical Manual of Mental Disorders, Fourth Edition, (DSM-IV) or, in Europe, the International Classification of Diseases, Tenth Edition, (ICD-10).
Symptoms must be observed in two environments such as at home and at school or at home and at work in order to meet the criteria. Additionally, the practitioner takes a detailed history of the individual’s difficulties both directly (by talking to the patient directly) and indirectly (by talking to the patient’s family members). Ideally, the history would include a list of the patient’s potential strengths and talents. The interview should also include a thorough screening for other psychiatric disorders.
Psychological Tests In addition to the DSM-IV and the ICD-10 criteria, a number of psychological tests can help to diagnosis ADHD. Among the most popular include The Conner’s Parent and Teacher’s Rating Scale for children and the Brown Attention Deficit Disorder Scale for adolescents and adults. Individuals with ADHD may also benefit from the Wechsler Intelligence Scales for Children, Fourth Edition and the Wechsler Adult Intelligence Scales, Third Edition. Whereas ADHD is unrelated to an individual’s overall intelligence, both these tests offer certain subsets that are fairly sensitive to the areas of the brain most affected by the disorder.
Medical Exam In addition to conducting a clinical interview, all diagnostic evaluations should include a medical exam. A number of medical conditions can either mimic ADHD-like symptoms or complicate the treatment. Conditions that produce ADHD-like symptoms include thyroid dysfunction, hearing loss and psychiatric disorders such as bipolar disorder. People with ADHD may also suffer from associated health conditions such as migraines, irritable bowel syndrome and substance abuse.
Additional Testing In addition to the clinical evaluation, practitioners may order additional tests to help confirm the diagnosis. The following is a list of the different types of tests:
- Medical: Most likely the medical exam will help to determine whether further testing is necessary. For example, a doctor might order a blood test to check for lead toxicity or thyroid dysfunction. Another useful tests screens for sleep disorders. Essentially, the test requires the individual to spend the night in a lab to check the quality of their sleep.
- Neurological: Whereas neurological testing is not required, it can be enormously helpful in making an ADHD diagnosis. The way it works is that the individual answers a series of simple questions designed to evaluate specific areas of the brain. Neurological testing can be particularly helpful when trying to identify associated learning disabilities.
- Analytical: Brain scan technology has enable practitioners to take a close look inside the head of someone with ADHD. Tests such as the MRI (magnetic resonance imaging), PET (proton emission computed tomography), SPECT (single photon emission computed tomography) and the QEEG qualitative electroencephalogram) can look at the amount of brain wave activity and blood flow. That said, these tests have never produced results consistent enough to be used diagnostically.
Thomas E. Brown, Ph.D., Attention Deficit Disorder: The Unfocused Mind in Children and Adults, New Haven and London: Yale University Press, 2005.
Edward M. Hallowell, M.D., and John J. Ratey, M.D. Delivered from Distraction: Getting the Most out of Life with Attention Deficit Disorder. New York: Ballantine Books, 2005.