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Beginning in about 1990, substantial increases in the rates of ADHD diagnosis and medical treatment were found in several nationally representative samples of US physician office visits. For example, between 1995–96 and 2007-08, the number of office visits at which an ADHD diagnosis was made increased by over 400% in adults — from 3.1 per 1000 visits to 14.5 per 1000 visits. And, the percent of adult office visits including both ADHD diagnosis and medication increased from 1.9 to 11.4 per 1000 visits.
Among children aged 5 to 18, between 1991–92 and 2008-09, rates of ADHD diagnosis increased nearly 4‑fold among boys — from 39.5 to 144.6 per 1000 — and nearly 6‑fold for girls — from 12.3 and 68.5 per 1000 visits. During this time, the rate of visits that also involved medication treatment increased by similar rates.
These substantial increases in ADHD diagnosis and medication treatment raise the question of whether these trends have continued. Several recent developments in the field suggest this may be the case. First, the introduction of new ADHD medications and associated may contribute to increases in medication treatment simply because additional options are available. Second, changes in ADHD diagnostic criteria in DSM‑V, i.e., required age of onset of symptoms increasing from 6 to 12 and reducing the number of symptoms required in teens and adults from 6 to 5, could contribute to an increase in individuals meeting a somewhat broader set of diagnostic criteria.
The New Study
In a study recently published online in the Journal of Attention Disorders, Diagnosis and treatment of ADHD in the United States: Update by gender and race (2017) examines this question using date from the National Ambulatory Medical Care Survey over 3 time periods: 2008-09, 2010-11, and 2012–13. This survey provides data on a nationally representative sample of US community-based physician office visits. Counts of visits in which an ADHD diagnosis was made are based on diagnosis codes included for each visit. Similarly, information on prescribed medication enables the determination of the number of visits during which one of eight ADHD medications was prescribed. Demographic information, e.g., age, gender, race, are also available for each visit. With these data, trends in ADHD diagnosis and medication treatment over this time period, and how that may have varied in relation to demographic variables, can be determined.
The Findings
1. Rates of ADHD diagnosis continue to rise — Between 2008-09 and 2012–13, visits to a community-based physician that involved an ADHD diagnosis increased by 36% among adults — from 18.5 to 25.3 per 1000 visits. For youth, the increase was 18.5%, from 93.1 to 110.3 visits per thousand. Thus, rates of ADHD diagnosis during physician office visits increased faster in adults but the number of diagnosed youth remains far greater.
2. Rates of ADHD medication treatment continue to rise — Among adults, the number of office visits where ADHD medication was prescribed increased by 21%, from 15.1 to 18.2 visits per thousand adults. For youth, the increase was 16%, from 74.3 to 86 per thousand youth. Thus, nearly 9% of all youth visits to community-based physicians during 2012–13 involved a prescription for ADHD medication.
3. The increase in diagnosis rates vary by gender — Among adults, the increase in rate of diagnosis was greater in males than in females, increasing by 52% in males and only 23% for females. For youth, the increase in the percent of office visits that involved an ADHD diagnosis was more similar, increasing by 22% in females and 17% in males.
4. The increase in medication treatment rates vary by gender — Among adult males, the number of office visits that involved prescribing ADHD medication increased by 30%; for adult females, the increase was only 13%. Among youth, the trend was reversed as office visits involving ADHD medication increased by 29% females and by only 10% in males.
5. There were a number of interesting findings related to age and race — Increases in the proportion of office visits that involve ADHD diagnosis and medication treatment are most rapid among those over 50, especially adults over 65. Between 2008-09 and 2012–13, the rate of increase among adults 65 and above was 348%; the absolute number of older adults receiving an ADHD diagnosis remained very low, however.
For youth, there was actually a significant decline in visits involving an ADHD diagnosis (down 24%) and medication treatment (down 51%) in children under 5. Rates increased in every other age group with the largest increases occurring in youth between 15 and 19.
Visits involving a diagnosis increased substantially more for black youth than for white youth — 69% vs. 23%. Similar trends were observed for visits involving the prescription of medication.
Summary and implications
Results from this study clearly indicate that other than for children under 5, the upward trend in ADHD diagnosis and medical treatment that began over 25 years ago remains firmly in place. The decline in treatment for youth under 5 may reflect recent AAP guidelines that highlight complications with establishing the diagnosis in young children and that recommend clinicians initiate a trial of behavior therapy before prescribing medication.
For adults, rates of diagnosis increased more rapidly during the 6‑year study period for males than for females. For youth, diagnosis is increasing a bit more quickly in females but the rate of “…population-adjusted growth in ADHD diagnosis coupled with pharmacotherapy for females was nearly triple than that for males over the 6‑year study period.” The latter may reflect greater vigilance on the part of physicians to identifying problems with attention, which tend to be more prominent in females with ADHD relative to hyperactive-impulsive symptoms.
While findings indicate that the rates of ADHD diagnosis and medication continue to increase significantly, these data provide no information on the reasons that these upward trends continue. It may be that the broadening of diagnostic criteria in DSM‑V has resulted in more individuals being diagnosed and treated medically than was previously the case. The introduction of new medications and associated marketing efforts by pharmaceutical companies may also play a role. Such questions can not be addressed by the survey data reviewed here, however.
It should also be noted that the study provides no information as to whether the accuracy of ADHD diagnoses has improved, i.e., are physicians just doing a better job of recognizing ADHD and diagnosing it appropriately. Results from a recently published study on pediatricians’ practices for diagnosis and treating ADHD suggest, however, that this is not likely to be the case — see Discouraging new findings about pediatric care for children with ADHD: Often, best-practice guidelines are not followed for a review of this study. This concern, coupled with findings that the rates of ADHD diagnosis vary significantly in different parts of the country, and are substantially lower in other developed countries, raise important questions about the need to better understand why the diagnosis and medication treatment of ADHD has continued to rise at a fairly rapid rate.
– Dr. David Rabiner is a child clinical psychologist and Director of Undergraduate Studies in the Department of Psychology and Neuroscience at Duke University. He publishes the Attention Research Update, an online newsletter that helps parents, professionals, and educators keep up with the latest research on ADHD, and helped prepare the self-paced, online course How to Navigate Conventional and Complementary ADHD Treatments for Healthy Brain Development.
