ADHD: Answers to Questions Physicians Often Ask

Is there a biomarker for the diagnosis of ADHD?

There are many exciting new studies of the biologic basis of ADHD that use neuroimaging and genetic testing. However, none of these methods can reliably diagnose this complex disorder. Someday, these technologies will be used to help subtype ADHD and improve treatment matching.

No, but such testing can identify associated learning disorders. Referral for testing is suggested when learning problems seem to be related to issues other than ADHD.

ADHD may be both overdiagnosed and underdiagnosed in the United States, depending on access to skilled professionals. When DSM IV criteria are strictly applied, the diagnosis is reliable. However, all inattention is not ADHD. Overdiagnosis occurs when inattention is the only criterion used to make the diagnosis.

When strict diagnostic criteria are applied, the prevalence of ADHD is about the same in all populations. The use of medications to treat ADHD is much greater in the United States than in other countries, however.

Good question! ADHD certainly is being diagnosed more frequently. But without a good population-based study, we do not know whether the incidence is increasing. Debates about whether there is an increase propose explanations ranging from overdiagnosis and treatment based on cultural differences to the role of environmental neurotoxicology.

The truth is nobody really knows.

Distractible inattention is the hallmark of ADHD in children and adults. Adults have less hyperactivity and more comorbidity. Diagnostic questions based on school performance and childhood activities need to be modified to apply to adult life when assessing ADHD in adults.

ADHD is less likely to be diagnosed in girls. Girls are more likely to have the inattentive subtype rather than the inattentive/impulsive subtype more commonly found in boys. Symptoms of the latter call more attention to the disorder.

No, but we do know it is a complex disorder with a strong biologic basis. It is not a culture-bound syndrome.

Consider post-traumatic stress disorder, psychosis, depression and anxiety disorders, and substance abuse.

ADHD is highly comorbid with depression (especially bipolar disorder), tics, and Tourette syndrome.

Excessive mood lability is usually only seen in bipolar disorder. Significant aggression is more likely with bipolar disorder. A positive response to ADHD medications for those with ADHD is another key diagnostic indicator. A family history of one or the other disorder is usually a good indicator.

Stimulants are usually the first line of treatment. Whether to start with methylphenidate( or amphetamine seems largely an individual preference. However, prescribing studies suggest that primary care physicians tend to start with methylphenidate, while child psychiatrists tend to prescribe more amphetamines. This is perhaps the result of perceived differences in side-effect profiles, treatments already tried, and stigma ("oh no, not speed!").

First, I review the diagnostic criteria and symptom targets with the parents. Then, I suggest a brief treatment trial to find out whether they and the child's teachers think the medication clearly makes a difference. The decision about whether to continue that drug can be made after that. I point out that the effects of the medication will be obvious in a short period.

I recommend that parents think about it, do their own reading, and then set a follow-up appointment to decide. Almost every parent of a child with ADHD agrees to the trial.

Most studies of particular diets for ADHD have not demonstrated a significant difference from placebo. However, some parents do report benefits when certain foods--particularly simple carbohydrates (eg, sugar)--are eliminated.

I don't generally support diets that remove children with ADHD from a "normal" life--unless the family follows such diets too.

There has been a great deal of interest in neurofeedback for the treatment of ADHD. There are a few studies, which are often done by the same authors and published in the same journals. Those studies support a change in brain function as a result of the technique, but it is not clear whether the effects are lasting. There seems to be no harm--except for expense.

Outcome studies do indicate a higher rate of substance abuse and conduct disorder in certain people with ADHD. But the studies also suggest a much better outcome with effective treatment.

Teachers are a valuable source of information. Their completed ADHD rating scales help validate and quantify the disorder and the effects of treatment. Teachers also can be blind raters for children who are trying medications.

I have found e-mail contact with teachers more dependable than phone calls.

Referral is indicated when you are not comfortable with the diagnosis, if you have tried 1 or 2 stimulants without clear benefit or with troubling side effects, or when comorbidity or family issues make treatment very complex.

There are many publications and Web sites. The American Academy of Pediatrics is developing a broad range of ADHD educational materials at www.aap.org. The American Academy of Child and Adolescent Psychiatry has Facts for Families, Practice Parameters, training videos, and pharmacology courses available on its Web site at www.aacap.org.