Monday, 14 September 2015

US Childhood ADHD / ADD figures on the up

"Has a doctor or health professional ever told you that (child) had attention-deficit/hyperactivity disorder (ADHD) or attention deficit disorder (ADD)?"

That was the question posed, answered and reported on in a recent edition of the CDC Morbidty and Mortality Weekly Report (MMWR) [1] (page 925).

Comparing positive responses to said question as part of the US National Health Interview Survey going back nearly 20 years (see attached graph), it appears that there is an upward trend in cases of pediatric ADHD/ADD (aged between 5-17 years old) based on parental report. This trend has been mentioned before (see here).

"From 1997–1999 to 2012–2014, the percentage of all children aged 5–17 years with diagnosed attention-deficit/hyperactivity disorder (ADHD) increased significantly from 7.0% to 10.2%." That's quite an increase over a relatively short period of time, surpassing previous estimates that I've discussed on this blog (see here).

Of course these figures are based on that single question answered by parents / primary caregivers over and above more external assessment and diagnosis. I would however be inclined to suggest that most parents would understand the question posed and would remember if a doctor or healthcare professional had uttered the words ADHD or ADD whether following formal assessment or under more speculative circumstances.

The differences reported according to ethnicity are interesting and perhaps tie into the question of what might be driving the increase in reports. "Throughout 1997–2014, Hispanic children were the least likely to have diagnosed ADHD" is one statement made and follows a baffling trend. An 'unfair prejudice' or perhaps some 'genetic' or biological protection are hypotheses that have been entertained over the years. One could likewise suggest that 'over-diagnosis' might be at work in other ethnic groups too as per other data [2]. I'm keeping an open mind on the question of 'why the increase' in light of the other discussions on other labels (see here and see here).

Whatever the reasons, the label of ADHD is here to stay. The recent report from Visser and colleagues [3] also provides some interesting information on some of the diagnostic experiences of children with ADHD too.

Music: The Script - Hall of Fame ft. will.i.am.

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[1] QuickStats: Percentage of Children and Adolescents Aged 5–17 Years with Diagnosed Attention-Deficit/Hyperactivity Disorder (ADHD) by Race and Hispanic Ethnicity — National Health Interview Survey,United States, 1997–2014. MMWR. August 28. 2015; 64: 925-925.

[2] Polanczyk GV. et al. ADHD prevalence estimates across three decades: an updated systematic review and meta-regression analysis. Int J Epidemiol. 2014 Apr;43(2):434-42.

[3] Visser SN. et al. Diagnostic Experiences of Children With Attention-Deficit/Hyperactivity Disorder. National Health Statistics Reports. 2015; 81: Sept 3.

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ResearchBlogging.org Polanczyk GV, Willcutt EG, Salum GA, Kieling C, & Rohde LA (2014). ADHD prevalence estimates across three decades: an updated systematic review and meta-regression analysis. International journal of epidemiology, 43 (2), 434-42 PMID: 24464188