A True ADHD Epidemic or an Epidemic of Overdiagnosis?

boy focused on coloring next to boy bored with head on table
boy focused on coloring next to boy bored with head on table

In 2011, the CDC reported that the prevalence of attention-deficit/hyperactivity disorder in children ages 4 to 17 years was 11%, with 6.4 million children diagnosed with ADHD and 4.2 million taking psychostimulants.1

These findings represent a dramatic increase from more than 30 years ago, when the rate of attention-deficit/hyperactivity disorder (ADHD) was estimated at between 3% and 5%.2 What is more concerning is that the prevalence of ADHD increased by about 35% just from 2003 to 2011, and there is no indication that this increase leveling out.1 More than 20% of high school-aged boys have been told they have ADHD!3


What is going on here? Have 11% of our children always had ADHD and we just missed it? Has some cataclysmic genetic or epigenetic shift taken place, causing ADHD to be the most prevalent childhood disease second only to obesity?  I don't think so. I believe that this dramatic increase in ADHD diagnoses is caused by two factors:

  1. Overdiagnosis through inadequate evaluation and societal pressure for treatment ; and
  2. A significant increase in the demands being made on our children, schools, and families.

It is important to recognize that a diagnosis of ADHD is contextual, meaning that a child with the same neurodevelopmental traits may be seen as having ADHD or not depending on his or her specific social and educational environment.

Making an accurate diagnosis of ADHD takes time. It is not a matter of just filling out a standardized form and giving a trial of medication. Physicians must rule out other conditions that may present with ADHD-like symptoms, such as learning disabilities, anxiety, and posttraumatic stress disorder (PTSD). It is important to get an understanding of the child's entire environment, including his or her school and family situation. One must take the time to speak with and observe the child before rushing to a diagnosis.

Yet how often is this possible? Practicing pediatricians and primary care providers are aware of the pressures to make a diagnosis and prescribe a stimulant. Teachers are demanding it of parents, as are parents whose resources of time and energy are strained to the limit. However, how many of our frontline providers have the time and resources to conduct an adequate evaluation?

Where I practice, near Silicon Valley, there are schools of very bright children where up to one-third or more are reported to be taking psychostimulants because of the academic pressure to succeed and be admitted to an elite university. 

On the other end of the spectrum, the prevalence of ADHD in Medicaid patients is 33% higher than that seen in the general population. The reasons for this are uncertain, but may well reside in the need to provide behavioral control in situations where there are inadequate services available.

If ADHD is a true neurodevelopmental disease—which it is—then the prevalence of diagnosis and treatment should be consistent. Yet there is dramatic difference in prevalence rates not only by state, but even by county. In 2011, the prevalence of ADHD in Kentucky was 14.8%, which was 250% higher than the 5.6% prevalence reported in Colorado.4 Although these statewide disparities exist across the United States, there is no reasonable biological explanation for these differences.

Consider this: In 2010 in a study in the Journal of Health Economics, 10% of kindergarteners born in August (youngest in class) were diagnosed with ADHD  compared with 4.5% of those born in September (oldest in class), and those born in August were twice as likely as those born in September to be treated with psychostimulants.5 The authors estimated that just this factor alone could have resulted in 900,000 incorrect diagnoses of ADHD.  Similar results were found in a Canadian study.6

In Iceland, a country with a relatively high use of psychostimulants, investigators found that the entire youngest third of the class was 50% more likely to be diagnosed with ADHD and prescribed psychostimulants.7 What these studies tell us is that we are unable to distinguish those children who have ADHD from those who are simply immature.

One could argue, and some do, that this might mean we are underdiagnosing the older children; however, I think it is much more likely that we are misdiagnosing children who are simply a little young for the demands being placed on them.

This leads me to the second major reason that I believe ADHD is overdiagnosed: the escalating demands made on children in our current educational system. When those of us who are now mature adults were in kindergarten, all that was required was to be able to eat, sleep, and play. Kindergarteners are now expected to learn to read. Of course, most of them can do so—although studies indicate there is no overall cognitive benefit to this earlier training8—but there are some children whose neurodevelopmental level is just not high enough for this level of challenge.

To clarify the point, what if we asked a few hundred 2-year-old children to sit still and focus on learning to read? How many would fit the diagnostic criteria for ADHD? It sounds absurd, but to a lesser but significant extent, this is what is happening in our kindergartens.

In addition, the diagnosis and treatment of ADHD in preschoolers is creating one of the most rapidly growing segments of the ADHD population. How many of us have been asked to diagnose a 3-year-old child with ADHD because they “won't sit still during circle time”? A generation or two ago, many children did not go to preschool and sitting still in a group was not one of the requirements of early childhood education.

Another aspect of this problem involves newer educational policies. In The ADHD Explosion, Stephen Hinshaw, PhD, demonstrated that educational accountability policies in schools have had a significant influence on ADHD rates.9 In the 1990s, policies such as “No Child Left Behind” (signed into law in 2001) began to incentivize schools to boost test scores.

Those states in which this occurred saw the largest increases in the diagnosis of ADHD. After all, with limited educational resources, what better way to quickly increase results than to simply give more children psychostimulants?

Finally, I believe the ever-increasing stress on the average American family is contributing significantly to this problem. Imagine the single-parent or two-working-parent family taking their sons and daughters to school or sometimes early school, working all day as the children go to after-care, and then rushing home to pick them up. They then try to get a decent dinner on the table before homework and bedtime.

The stress on both parents and children is very high. This stress can result in children who may have been able to cope under different circumstances, but who appear to have ADHD in this context (and that also doesn't consider the influence of poor nutrition on these children, which is a subject for another day and another column).

In summary, I do believe that we have an “epidemic” of overdiagnosis of ADHD, the roots of which are deeply ingrained at many levels in our society. We will have to decide whether to treat more of our children with long-term psychostimulants or work together to find a different approach to this persistent problem.

Sanford C. Newmark, MD, is the head of the Pediatric Integrative Neurodevelopmental Program at the Osher Center for Integrative Medicine at the University of California, San Francisco. He is also the author of the book ADHD Without Drugs — A Guide to the Natural Care of Children with ADHD. 

References

  1. Centers for Disease Control and Prevention. Attention-deficit/hyperactivity disorder (ADHD): data & statistics. New data: medication and behavior treatment. Available at: http://www.cdc.gov/ncbddd/adhd/data.html. Accessed July 28, 2015.
  2. Miller RG, Palkes HS, Stewart MA. Hyperactive children in suburban elementary schools. Child Psychiatry Hum Dev. 1973;4(2):121-127.
  3. Visser SN, Danielson ML, Bitsko RH, et al. Trends in the parent-report of health care provider-diagnosed and medicated attention-deficit/hyperactivity disorder: United States, 2003-2011. J Am Acad Child Adolesc Psychiatry. 2014;53(1):34-46.
  4. Centers for Disease Control and Prevention. State-based prevalence data of parent reported ADHD diagnosis by a health care provider.  Available at: http://www.cdc.gov/ncbddd/adhd/prevalence.html#current/. Accessed July 28, 2015.
  5. Evans WN, Morrill MS, Parente ST. Measuring inappropriate medical diagnosis and treatment in survey data:  The case of ADHD among school-aged children. J Health Econ. 2010;29(2010):657-673.
  6. Morrow RL, Garland J, Wright JM, Maclure M, Taylor S, Dormuth CR. Influence of relative age on diagnosis and treatment of attention-deficit/hyperactivity disorder in children. CMAJ. 2012;184(7):755-762.
  7. Pottegård A, Hallas J, Hernandez-Diaz , Zoëga H. Children's relative age in class and use of medication for ADHD:  A Danish nationwide study. J Child Psychol Psychiatry. 2014;55(11):1244-1250.
  8. Carlsson-Paige N, McLaughlin GB, Almon JW. Reading instruction in kindergarten: little to gain and much to lose. January 2015.  The Alliance for Childhood and Defending the Early Years. Available at: https://deyproject.files.wordpress.com/2015/01/readinginkindergarten_online-1.pdf. Accessed July 28, 2015.
  9. Hinshaw SP, Scheffler RM. The ADHD Explosion: Myths, Medication, Money, and Today's Push for Performance. New York, NY: Oxford University Press; 2014.
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