ADHD, IQ, and Giftedness

hi everyone Russ Barkley here and in today's commentary I want to speak with you about the relationship of ADHD to intelligence in general and specifically to giftedness claims have been made going back some 30 or more years now that people with ADHD particularly adults may be more likely to be gifted than other individuals or certainly of high levels of intelligence we've also heard the reverse claim the possibility that gifted individuals may be more likely to have ADHD and manifested in the classroom primarily because they're bored I'm going to look at both sides of that argument

but let's begin with this Association of ADHD with intelligence and I'm going to use this particular friend of ours the old bell curve and here we see the bell curve of intelligence in the general population and most people place here within the average range but we also have individuals who are way up here about two standard deviations above the norm the norm being about an IQ of a hundred plus or minus 15 and this being IQs of about 130 or higher depending on how you want to Define giftedness and then of course there's a group

of individuals who place at the lower end of the bell curve and we would consider these individuals to be intellectually deficient and what used to be called mental retardation but obviously that ID diagnosis is based on other things besides IQ but the point is here's our range of intelligence in the population what do we see in research on ADHD first we see that there is a negative correlation between severity of ADHD and level of intelligence correlation is about 0.3 means that the 2 two traits share about nine percent variation and the higher your ADHD symptoms

are you're going to be slightly below the norm average about seven to ten points lower than individuals in the typical population so it's a very small difference people with ADHD span the whole range of intelligence from intellectually disabled all the way up to gifted but on average as a group untreated individuals with ADHD Place slightly lower than the typical population they would have a bell curve and its peak would be somewhere right about here in other words the two curves would overlap substantially that's my point people with ADHD span the entire range of typical people

but their Peak IQ would be somewhere right around it here again about seven to ten points lower than average that's been found in hundreds of studies meta-analyzes of measures of intelligence and executive functioning and so on so it's a fact in the bag it's not disputable on the other hand why does that occur one possibility is that people with ADHD don't take IQ tests very well their symptoms interfere with test taking makes perfect sense there have been studies that have looked at that and they've put some individuals with ADHD on medication and other individuals not

they've also tested people on and off their medication and what they find is that yes test taking Behavior does account for a few points in this seven to ten point difference so correct test taking could be part of the problem in other words there's not as much of a difference between ADHD and typical people other than in test taking the second possibility is that ADHD interferes with executive functioning we've talked about that in many of my lectures here about 40 percent of your IQ is executive functioning roughly we can see that because some of the

subtests on IQ tests are things like working memory among other executive functions so it's possible that there is a direct effect of ADHD on IQ because of its adverse effect on the executive function so that could explain a few percentage points here and Studies have been done that have controlled for executive functioning and looked at these IQ differences and indeed some of the IQ difference is related to Executive functioning deficits but not all of it so there's a few percentage points left that is not explained by test taking or by executive functioning it's possible that

those few points lower an IQ are the result of some people with ADHD have acquired their ADHD it's resulted in brain injury and that brain injury would explain some of the lower intellect in those individuals upwards of about 25 to 35 percent of people with ADHD acquired it they didn't inherit it it's not genetic it's the result of injuries to the brain either prenatally during brain development or in early childhood such as traumatic brain injury or later in adulthood for a variety of causes so that might explain some of the residual differences again people with

ADHD span the same range of intelligence as people without ADHD but overall on average there's slightly lower levels of intelligence for various reasons what does that mean are people with ADHD therefore more likely than typical people to be gifted absolutely not if anything all of this evidence suggests the opposite there's a slightly lower percentage of giftedness among those with ADHD it's probably very small you'd have to have huge studies samples that is to find it but the point is all this evidence gives the lie to the claim that was started more than 30 years ago

that people with ADHD are more likely to be gifted or of higher levels of intelligence than other individuals they're not they're just like the rest of us they span the entire range of intelligence so there you have it people with ADHD are not more likely to be gifted now let's move on to a couple of papers here that I want to talk about let's take a look at our people who have ADHD and are gifted different from other people who are gifted or different from people with ADHD who aren't gifted this is a study of

children there are several like this I'm just going to illustrate this one that's in the international Journal of mental health and addiction and they compared children at all three of those groups typical but gifted ADHD and gifted and just ADHD average not gifted what did they find what they found is that the disorder of ADHD is the same in the gifted and non-gifted ADHD group but the gifted individuals had slightly less severe symptoms still met the criteria but milder symptoms and we've seen this as I said in other studies so if anything what we see

is that gifted individuals are slightly less likely to have ADHD and if they do have ADHD it's somewhat less severe than the typical population but the differences are pretty minor if we compare gifted people with ADHD to gifted people without ADHD we of course see that the gifted with ADHD have massive symptoms of ADHD after all they met the diagnostic criteria for it but what does all of this mean in these comparisons it means that giftedness and ADHD are two distinct things and they don't overlap very much at all and when they do overlap you're

gifted and your ADHD you can have both of these conditions it's not like one is masquerading as the other it's not as if the gifted people are more likely to have ADHD or ADHD people are more likely to be gifted the two conditions can coexist and probably do so at about the same rate in the population maybe a little bit less likely to be ADHD among the gifted now let's look at the reverse claim and that is that kids who are gifted let me go to the top here are more likely to be called ADHD

and to have ADHD after all if they're unchallenged in the classroom and they're bored the claim is that they're going to show a lot of ADHD type symptoms first of all I find this going to be ridiculous just being bored doesn't put you in the clinical range of ADHD or where you've got at least six to twelve of the symptoms of ADHD to a significant clinical degree that just doesn't make any sense so yeah you might be a little bored and a little inattentive but I don't find that particularly compelling so where did this idea

come from well this article examines the background for this claim and finds that there's very little of any evidence for the idea that gifted people are more likely to have ADHD this is in the journal Apex and as you can see here excuse me it's by Kylie Edwards but if we go on down here what we find is that gifted individuals are less likely to show symptoms of ADHD which we found in those other research papers not more likely to have the symptoms of ADHD and what this article does is to go through and call

pull together the comments of experts teachers and others on what are the attributes of gifted individuals and are those attributes in any way overlapping with ADHD and we can see here multiple attributes in the area of learning characteristics the gifted demonstrate a variety of Behavioral and cognitive attributes that are different from typical individuals but if you'll scan down this list none of these overlap with ADHD in fact if anything people with ADHD would be less likely to demonstrate some of these particular learning attributes such as independently seeks to discover why and how things happen and

formulates ideas with evidence and so on I mean people with ADH are likely to do that too but that's not part of their ADHD certainly not a DSM symptom in the area of creativity if we look down this list none of these symptoms of giftedness if we can call them that attributes of giftedness overlap with ADHD again if anything they go in the opposite direction that's especially true here when we look at the motivational characteristics of gifted individuals self-directed High self-motivation very persistent very committed reliable and so on and prefer to work independently these are

almost the Opposites of the complaints we hear from people with ADHD because of their self-motivational and executive and self-regulatory deficits and then finally down here look at leadership characteristics and you'll see that none of these are symptoms of ADHD in any way and if we go and take a look at that self-determination set of characteristics again we see little if any overlap with symptoms of ADHD often the opposite except One symptom that I've highlighted here is easily bored with routine tasks that's it so based on this we can say that the attributes of gifted people

are not the attributes of ADHD in many cases they're the opposite of that we can also conclude that people with ADHD can be gifted and gifted people come out ADHD and when we see the two together both occur together one isn't explaining the other and as I've said we've already shown that people with ADHD span the entire range of typical population IQ they're just like us if there's a small difference it's slightly negative a few IQ points lower on average but individuals with ADHD can span the whole range from intellectually disabled all the way up

to gifted as I've said before so I think we can say that these claims that were made over the past 30 years of people with ADHD being highly intelligent people with ADHD being more likely to be gifted and also the opposite gifted people being more likely to be ADHD are not true people with ADHD are just like the typical population in these attributes so thanks for joining me for this commentary and I hope you see around this Channel with other commentaries and news on recent research pick here and be well