ADHD Really Increasing? I Can't Keep Paying Attention

After reading about a new ADHD study in the news I feel a little inattention and spontaneous outbursts coming on. Try to focus now because it will get confusing.  

The mainstream media couldn't figure out whether a new study finding rising ADHD diagnoses reflected a real increase in the condition or better awareness. At least that's the way the media framed a recent study out of Southern California in JAMA finding rates of new ADHD diagnoses in kids aged 5 to 11 rose from 2.5% in 2001 to 3.1% in 2010. That's a 24% increase in less than a decade.  
Are more kids truly suffering from hyperactivity and attention deficits, or are we simply better at catching children who show any symptoms? ADHD Diagnoses Continue to Climb, Time Healthland
Great question. The answer? It depends. Mainly on the news organization. 

Most hedged their bets, reporting the study offered evidence of a true rise and heightened awareness, either indirectly or directly but usually without sufficient explanations one way or another. Some decided to stress better awareness, others, a real increase.  

Let's take the real increase explanation. Why would this study support it?

It's not obvious.

The study included a large and diverse sample of 840,000 kids enrolled in the Kaiser Permanente healthcare system. Yes, a nice fat data set so the researchers were able to look at new ADHD rates among a variety of ethnic groups. If awareness and access were equal among the groups, we'd expect rates to be more similar across ethnic groups. This never quite makes it to the media reports. It's an important assumption. In this study the ethnic gap appeared to close (save the Asians, get to them in a minute). Also new diagnoses rates increased for White, Hispanic and African-American kids (especially African-American girls) but not Asian American kids whose parents were more likely to forgo mental health services, their rate remained at 1.1%. I suppose the rising rates, because they were plentiful for everyone except the Asians, even the already highly-diagnosed White kids though to a lesser extent, point to real increases too:
New ADHD Diagnoses by Ethnic Groups in 2001 and 2010: 
White: 4.7% - 5.6% (@30 increase 
Black: 2.6%- 4.1% (@70% increase) 
Hispanic: 1.7 - 2.5% (@60% increase)
Basically some suggested the study showed a true rise in part because all kids had medical coverage in the program, all had access or "awareness" or at least hypothetical access to people who'd likely be aware given their participation in health care system. If awareness/access is equal, then it's a real rise. Some hinted at group differences as evidence of a true rise.  
The size of the study, and the variation in ADHD diagnosis rates among different populations, supports the idea that not all of the rise can be attributed to increased awareness among doctors, teachers and parents of the disorder. ADHD Diagnoses Continue to Climb, Time Healthland
Though the article never spelled out exactly why these factors support the real rise theory. This was the final line so it was left to the reader to resolve. Again, it has to do with all things equivalent, groups should show similar rates. The size of the study, by the way, is not a good piece of evidence either way. 

Now it's a stretch to say all the kids had equal access and awareness. Obviously I'm not as certain as the authors of the study who've mentioned it. Nor apparently was the New York Daily News that went with better awareness in their sub-title: 
The proportion of five- to 11-year olds diagnosed with ADHD increased from 2.5 percent in 2001 to 3.1 percent in 2010, a large jump that researchers think may be due in part to heightened awareness of the condition. ADHD diagnoses spike in the past decade, California study finds 
One of the authors also stressed awareness. At least that's the comment Science Daily typed up:
While the reasons for increasing ADHD rates are not well understood, contributing factors may include heightened awareness of ADHD among parents and physicians, which could have led to increased screening and treatment," said Dr. Getahun. Childhood Diagnosis of ADHD Increased Dramatically Over 9-Year Period, Science Daily
Obviously more and more kids, save the Asian kids, are coming down with a case of inattention and poor impulse control. I understand the feeling...

Speaking of the Asian kids, one of the authors also pointed out another important factor in ADHD rates because obviously we have no reason to believe Asian kids are immune to ADHD:
"Our study findings suggest that there may be a large number of factors that affect ADHD diagnosis rates, including cultural factors that may influence the treatment-seeking behavior of some groups," said study lead author Darios Getahun, MD, PhD, from Kaiser Permanente Southern California's Department of Research & Evaluation. Childhood Diagnosis of ADHD Increased Dramatically Over 9-Year Period, Science Daily
Others not affiliated with the study played down the role of better awareness and favored a true rise perhaps for their own reasons (i.e. highlighting the pernicious role of environmental triggers):
Even if some of the reported increase is due to better awareness, these data seem to speak to a true increase. There's a fairly substantial list of environmental factors that have been linked to ADHD," says Dr. Philip Landrigan, Director of the Children's Environmental Health Center at Mount Sinai School of Medicine. California Data Shows ADHD Cases Rising, CNN Health           
Here's their argument translated:

We see a real increase in these numbers. Forget "seem to speak." We're sure it's there somewhere and hey, look at all the evidence we have over here in the Environmental Toxin Lab, forget about their data, look at ours.  

All the uncertainty and mixed messages stand as proof this study offered up less than definitive evidence of the particular extent to which increasing rates reflect anything be it true increases of ADHD, increased awareness, increased access or increased patience among the field researchers combing through 840,000 medical records. That said, it's reasonable to talk about better awareness or access as responisble for some of the increase, especially among the Black and Hispanic kids who appeared to be "under-diagnosed" to some extent. It's not like these groups suddenly began showing symptoms (and did not 10 years ago). It's reasonable to expect some was due to increasing symptomotology.

Just in case you are not confused enough, your mind distracted by the mixed messages, here's one more important detail frequently left out of the media.This study addressed new diagnoses and not the overall rates (i.e. the entire % ever diagnosed). Some articles failed to clarify that point or muddled it. 

The CNN Health blog, The Chart kinda sorta got it but then kinda lost it:

First the total rate of cases, new and existing.
Overall, in 2001, 2.5% of children aged 5 to 11 were diagnosed with ADHD, but that number crept up to 3.1% by 2010. California Data Shows ADHD Cases Rising, CNN Health               
Then this later confusing use of "overall."
Still, the overall rate of ADHD diagnosis was highest in white children, at 5.6% in 2010. California Data Shows ADHD Cases Rising, CNN Health
Another note. The present study looked in medical records for evidence of ADHD a diagnoses.  Earlier studies that have taken the word of parents such as the National Health Interview Survey (1998-2009) tended to find higher rates.  
The percentage of children ever diagnosed with attention deficit hyperactivity disorder (ADHD) increased from 7% to 9% from 1998–2000 through 2007–2009. NHIS, via the CDC                                                                                                                  
BTW if in 5 years you should read ADHD is increasing among Asians, do not automatically assume they suddenly started coming down with ADHD.

Phew. Done. If you are still reading this in my totally unprofessional opinion you likely do not have ADHD. 

Recent Trends in Childhood Attention-Deficit/Hyperactivity Disorder.erDarios Getahun, MD, PhD; Steven J. Jacobsen, MD, PhD; Michael J. Fassett, MD; Wansu Chen, MS; Kitaw Demissie, MD, PhD; George G. Rhoads, MD, MPH
JAMA Pediatr. 2013;():1-7. doi:10.1001/2013.jamapediatrics.401.

1 comment:

Meghan said...

I will remember this when the study comes out saying ADHD is on the rise in Asian kids.