The study, published in the January 21 2013 online edition of JAMA Pediatrics
, examined trends in ADHD diagnosis by race/ethnicity, age, sex, and household income. It followed the health plan medical records of 842,830 children aged 5 to 11 years who received care at Kaiser Permanente Southern California from January 1 2001 through December 31 2010. The researchers specifically looked at incidence of physician-diagnosed ADHD.
Overall, rates of ADHD diagnosis rose from 2.5% in 2001 to 3.1% in 2010 - a 25% increase over the 10-year period. The rates of ADHD have reached epidemic proportions, said the researchers in a report by MedPage Today
Throughout the entire study, white children had the highest rates of ADHD diagnosis. However, the largest increases
in diagnosis rates were seen in black and Hispanic children. From 2001 to 2010, the ADHD diagnosis rate in whites rose from 4.7% to 5.6%; in blacks it rose from 2.6% to 4.1%; and in Hispanics, the rate rose from 1.7% to 2.5%. This translates into a 30% increase in whites, 67% in blacks, and 60% in Hispanics. In contrast, ADHD diagnosis rates for Asians/Pacific Islanders remained unchanged at around 1%.
Although, overall, boys were more likely to be diagnosed than girls, researchers attributed the increase in diagnosis in blacks to an increasing likelihood of diagnosis in black girls specifically.
Age of diagnosis was quite steady throughout the study, at 8.4 to 9.5 years of age. Patients with ADHD were more likely to be from higher income families.
The study was funded by Kaiser Permanente Direct Community Benefit Funds and no conflicts of interest were reported by the researchers.
So what is fueling this trend in ADHD diagnosis rates? The researchers didn't speculate and so this reporter will try, going solely from anecdotal evidence from friends, neighbours and family, and projects I have written. First, in order to get an ADHD diagnosis, a parent needs to seek one out. Usually this occurs because a teacher is concerned about their child's behaviour in school. More teachers are complaining, so more parents are seeking diagnosis, usually to obtain accommodations at school, and sometimes also for medication. Perhaps ADHD is just the trend right now; after all, I've lost track of how many parents have come to me saying their teacher thinks their child has ADHD. Most of the parents who confided in me have boys (overall, ADHD is diagnosed three times more frequently in boys than girls) and so I personally think part of the problem is that some teachers have trouble relating to boys' enthusiasm and energy. That may be an oversimplification, of course, but it is something to consider.
In terms of race, whites have been most keen on diagnosis from the start so it makes sense that they would have less of an increase than blacks or Hispanics who may have become interested in ADHD more recently. On the other hand, Asians, especially the newer immigrants (at least the ones I know here in this highly Asian community I live in), are still quite 'traditional' in that they like to focus on discipline and doing extra work, rather than accommodations; pride may be another reason they don't seek diagnosis.
One thing to remember is that the study focused on children whose parents had already sought and received a diagnosis. This gave us the diagnosis rates, but not necessarily the actual rates of ADHD across different races/ethnicities.