Open Journal of Psychiatry, 2011, 1, 56-65 OJPsych
doi:10.4236/ojpsych.2011.12009 Published Online July 2011 (http://www.SciRP.org/journal/OJPsych/).
Published Onl ine July 2011 in SciRes. http://www.scirp.org/journal/OJPsych
Executive function impairments in high IQ children and
adolescents with ADHD
Thomas Edwa rds Brown, Philipp Christian Reichel, Donald Michael Quinlan
Department of Psychiatry, Yale University School of Medicine, New Haven, U.S.A.
Received 7 June 2011; revised 1 July 2011; accepted 9 July 2011.
ABSTRACT
Objective: To demonstrate that high IQ children and
adolescents diagnosed with ADHD tend to suffer
from executive function (EF) impairments that: a)
can be identified with a combination of standardized
measures and normed self-report data; and b) occur
more frequently in this group than in the general
population. Method: From charts of 117 children and
adolescents aged 6 to 17 years with high IQ ( ≥ 120)
who fully met DSM-IV diagnostic criteria for ADHD,
data on 8 normed measures of executive function (EF)
were extracted: IQ index scores for working memory
and processing speed, a standardized measure of au-
ditory verbal memory, and 5 clusters of the Brown
ADD Scale, a normed, age-graded rating scale for
ADHD-related executive function impairments in
daily life. Significant impairment was computed for
each individual relative to age-appropriate norms for
each measure and comparisons were made to base-line
rates in the general population. Results: Sixty-two
percent of participants were significantly impaired on
at least 5 of these 8 markers of EF. Chi-square com-
parisons of scores from these high IQ participants
were significantly different (p < 0.001) from standar-
dization norms for each of the eight EF measures.
Conclusions: High IQ children and adolescents with
ADHD, despite their cognitive strengths, tend to suf-
fe r f ro m s ignificant impairm ents of exe cutive functions
that can be assessed with these measures ; incidence of
these impairments is significantly greater than in the
general population. These results are fully consistent
with data on high IQ adults diagnosed with ADHD.
Keywords: ADHD; Executive Functions; High IQ;
Working Memory; Processing Speed
1. INTRODUCTION
In our clinical practice, often children and adolescents
with IQ scores in and above the superior range are
brought by their parents for evaluation and treatment of
chronic impairments related to symptoms of ADHD.
Many of these parents report that they have been told
repeatedly by teachers, clinicians and others that their
son or daughter was very bright, but doing poorly in
school because of chronic problems with inadequate
focus, inconsistent effort, insufficient organization, and
excessive forgetfulness. When the parents have inquired
as to whether these difficulties of their offspring might
be due to an attention deficit disorder, many have been
told that such problems do not occur among individuals
with such high levels of intellectual ability.
Clinically, parents of these very bright students report
that their son or daughter has always been able to work
very effectively on certain tasks in which they have
strong personal interest. Yet these students who demon-
strate strong motivation and impressive cognitive
strengths on those specific tasks that interest them tend
to have much greater difficulty than most of their peers
in trying to make themselves do homework, studying,
and other important tasks that do not, for them, hold the
same intense interest. Many of these students had earned
grades in the A range throughout most of their schooling,
but had been dropping into the low C to D range over the
preceding two years. When provided treatment appropri-
ate for ADHD, these very bright students often show
significant improvement in their ability to work effec-
tively while their medication is active.
While there are some data showing that groups of
children diagnosed with ADHD tend to have lower
full-scale IQ scores than children without ADHD [1],
other studies demonstrate that high IQ individuals can
suffer from this disorder. Katusic, Voight, Colligan, and
colleagues [2] reported data from 331 children in a pop-
ulation-based birth cohort study. They found core symp-
toms and age of onset of ADHD, rates of comorbid
learning and psychiatric disorders, rates of substance
abuse, and rates of treatment to be similar across 34

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
57
children with high IQ, 276 with normal IQ and 21 with
low IQ who fully met diagnostic criteria for ADHD.
Thus far the scientific literature has provided little evi-
dence of the nature of the cognitive impairments expe-
rienced by persons with high IQ and ADHD and whether
those impairments differ significantly from those of oth-
ers with ADHD or from t he ge neral pop ulation.
One study by Antshel, Faraone, and colleagues [3]
described 49 high IQ ( ≥120) children who fully met
DSM-IV diagnostic criteria for ADHD and showed a
pattern of cognitive, psychiatric and behavioral features
typical of children with average IQ diagnosed with
ADHD. They found that these very bright children with
ADHD tended to have significant difficulty with
schoolwork; 22% had repeated a grade at least once,
while only 3% of matched controls had ever been re-
tained. These children also had more comorbid psycho-
pathology and were more impaired in multiple domains,
relative to similarly bright children without ADHD.
Moreover, incidence of ADHD among first degree rela-
tives of these bright children with ADHD was much
higher (22.9%) than among such relatives of matched
controls (5.6%). Antshel et al. [3] concluded that the
diagnos i s of ADHD can be v a l id in high IQ c hildren.
In a follow-up study, Antshel and colleagues [4]
demonstrated that over a 4.5 year period high IQ child-
ren with ADHD, in comparison to high IQ controls
without ADHD, continued to have higher rates of mood,
anxiety and disruptive behavior disorders. Participants
with ADHD also continued to demonstrate elevated rates
of impairment relative to controls across most social,
academic and family function domains. The high IQ
scores of both groups persisted without significant
change over the 4.5 year follow-up period.
While studies by Katusic [2] and Antshel [3,4] have
demonstrated that high IQ children can fully meet diag-
nostic criteria for ADHD, and Antshel has shown that
high IQ students demonstrate significant problems in
their schoolwork, those studies did not identify specific
cognitive functions underlying academic underachieve-
ment of their samples.
Over the past decade there has been increasing recog-
nition that symptoms of ADHD enumerated in the
DSM-IV-TR constitute a syndrome of developmental
impairments of self-regulation that overlap with the
concept of Executive Function [5-10], a term that refers
to activities of a variety of brain circuits that prioritize,
integrate and regulate other cognitive functions. Miyake,
Friedman, et al. [11] described EF as general purpose
control mechanisms that modulate operation of various
cognitive subprocesses and thereby regulate the dynam-
ics of human cognition. These functions develop slowly
over the first two decades of life to manage the brain’s
cognitive functions and provide the mechanism for the
multiple aspects of “self-regulation” in daily life [12,13].
ADHD increasingly is being recognized as essentially
developmental impairment of these self-regulatory func-
tions.
EF impairments are not equivalent to overall impair-
ments of cognition measured by standard tests of IQ.
Delis and colleagues [14] did a large scale correlational
study between measures of EF and measures of IQ using
data from 470 normal functioning children and adoles-
cents. Their data demonstrated that IQ and EF skills are
divergent cognitive domains and that IQ tests do not
provide a sufficient or comprehensive assessment of
higher-level executive functions. IQ measu res accounted
for only 0% to 18% of the variance on variou s measures
of EF administered in that study. Similar conclusions
about the inadequacies of IQ tests for assessing EF were
reported by Ardila, Pineda and Rosselli in their study of
50 students’ ages 13 to 16 years [15].
This view of IQ and EF as independent of one another
is also supported by data from Rommelse, Altink, et al
[16] whose large study of children with ADHD vs. con-
trols found that group differences on EF were not ex-
plained by group differences on IQ and vice versa. In
principal components analysis that study also demon-
strated that EF and IQ are relatively independent of each
other in the same child. This is co nsistent with the argu-
ment of Schuck and Crinella [17] that children with
ADHD do not necessarily have low IQ; they demon-
strated that correlations between EF measures and IQ
scores account for less than 5% of the variance.
Many studies, e.g. Seidman [18-20]; Doyle and col-
leagues [21,22]; Martinussen and Hayden [23]; Mar ti-
nussen and Tannock [24]; McInnes, Humphries, et al,
[25]; Quinlan and Brown [26]; Shanahan, Pennington, et
al,[27]; Bedard [28] and Rapport, et al. [29] have re-
ported that children and adolescents with ADHD tend to
show impairments of executive functions (EF) such as
working memory, processing speed, and auditory verbal
memory. Yet these studies have not addressed whether
those with ADHD and high IQ manifest such weak-
nesses.
Seidman [18-20] and Doyle and colleagues [21,22]
used neuropsychological measures of EF to assess im-
pairments of executive function in children and adoles-
cents with ADHD. They found that about 30% of child-
ren and adolescents in their ADHD sample were signifi-
cantly impaired on traditional neuropsychological tests
of EF. They concluded that psychometrically defined
impairments of EF should be considered a comorbid
problem that is present in about one third of individuals
with ADHD, a comorbidity that compounds the already
compromised school functioning of children and ado-

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
58
lescents with ADHD.
While such findings from neuropsychological “tests of
EF” clearly identify individuals who suffer from severe
impairments of EF, it is not clear that such tests are suf-
ficiently sensitive to pick up the full range of EF im-
pairments that are characteristic of individuals with
ADHD. Investigators of executive functions in the el-
derly [30,31] and some researchers in ADHD [6-10]
have argued that the complex, multifaceted nature of
executive functions is such that traditional neuropsy-
chological “tests of EF” are not valid measures of EF
impairments, because they “fractionate” these integrative
functions, are too situationally specific, and have too low
a ceiling to be sufficiently sensitive. They argue that
clinical interview and rating scale data provide more
adequate measures of the w ide range of EF impairments
found in persons with ADHD. This may be particularly
relevant among those with higher IQ. In a sample of
adults with ADHD, Biederman, et al. [32] demonstrated
that neuropsychological testing of EF identified individ-
uals with relatively lower IQ and ach ievemen t test scores,
while questionnaire-based assessments of EF impair-
ments identified adults with higher levels of ADHD
symptoms, psychiatric comorbidity and interpersonal
deficits.
Limitations of neuropsychological “tests of EF” were
shown by Shallice and Burgess [33] who demonstrated
that patients with frontal lobe damage were unable ade-
quately to perform everyday errands that required plan-
ning and multi-tasking, even though they achieved av-
erage or well-above-average scores on traditional neu-
ropsychological tests of language, memory, perception,
and “executive functions.” Similar results from assessing
EF impairments in “real life” situ ations wer e reported by
Alderman and others [34] who assessed adults doing
tasks in a shopping mall. Wilcutt, et al. [35] reviewed
published studies and found that current neuropsycho-
logical tests are not sensitive enough to pick up ADHD
symptoms in children or adolescents. Brown [10] and
Barkley [7] have summarized theoretical and practical
issues underlying these conflicting views of EF in
ADHD. They argue that all individuals with ADHD suf-
fer from impaired EF that ADHD is essentially deve-
lopmental impairment of EF.
Most studies of EF impairments, however measured,
in those with ADHD have involved participants with a
wide range of IQ. They did not address the issue of
whether individuals with ADHD and high IQ demon-
strate the same problems of EF as do those in the wider
range of IQ scores. Most of these other studies, includ-
ing Antshel, et al., [3,4] did not administer a full IQ test
to their subjects; they estimated IQ from just a few key
subtests. This method is adequate for estimation of over-
all cognitive abilities, but it does not provide data ne-
cessary for comparing various combinations of subtests
useful for assessment of a person’s relative strengths and
weaknesses in cognitive abilities.
The study reported here used a combination of stan-
dardized measures and rating scale data to test the hypo-
thesis that children and adolescents with high IQ ( ≥ 120)
diagnosed with ADHD suffer from executive function
(EF) impairments that: 1) can be identified with a com-
bination of standardized measures and rating scale data;
and 2) tend to occur more commonly in this group than
in the gene ra l population.
2. METHODS
2.1. Sample
After approval from the Human Investigations Commit-
tee of Yale University, charts of all children and adoles-
cents who came during a four year period for evaluation
in either of two ADHD clinics, one private, another in a
university medical center, were reviewed to select every
patient aged 6 to 17 years diagnosed with DSM-IV
ADHD, any type, who had high IQ as defined by WISC
III/IV [36,37] or WAIS-III [38] index scores for Verbal
Comprehension (VCI) and/or Perceptual Organiza-
tion/Perceptual Reasoning (POI) ≥120 (top 9% of popu-
lation). These index scores were selected because they
are measures of overall cognitive abilities less sensitive
to cognitive impairments associated with EF. Full-scale
IQ scores and factor scores for Verbal and Performance
IQ on these Wechsler tests would be less valid because
they incorporate several subtests that assess working
memory and processing speed, aspects of EF.
Charts of all patients between the ages of 6 years and
17 years diagnosed with ADHD and scoring at o r above
the ≥120 cutoff for VCI or POI were included. Of the
obtained 117 patients, 75% were male. ADHD diagnosis
for these patients had been made on the basis of school
reports and extended clinical interviews with parents and
child. Each fully met DSM-IV diagnostic criteria for
ADHD. Subtype classification, based on current im-
pairments, was 62% Predominantly Inattentive Typ e and
38% Combined Type. Within the sample 26% were aged
6 to 11 years, 24%; 12 to 15 years, and 50% were 16 -
17 years.
A significant percentage of our sample of high IQ
youths with ADHD also currently met diagnostic criteria
for one or more additional psychiatric disorders. Most
frequent comorbidities were anxiety disorders 25%,
dysthymia or unipolar depression 21%, and specific
learning disorders 18%. Other disorders occurring in
more than 5% of the sample included obsessive compul-
sive disorder 15%, Asperger ’s disorder 11%, opposition-
al defiant disorder 10% and cannabis abuse 9%. No cur-

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
59
rent comorbidities were found in 39% of the sample
while 37% met diagnostic criteria for one additional di s-
order; 16% for two, and 8% for three or more comorbid-
ities. Cannabis abuse was found only in youths who
were 14 years or older. No patients with psychosis, bi-
polar disorder, or autism were included.
2.2. Measures
This study assessed charts of children and adolescents
with high IQ who met DSM-IV diagnostic criteria for
ADHD to determine their relative impairment on stan-
dardized measures of 3 executive functions: working
memory, processing speed, and short-term auditory ver-
bal memory, and on 5 clusters of EF assessed by parental
report (6 to 12 year olds) or self-report (12 to 17 year
olds) on the Brown ADD Scales, normed rating scales
for ADHD-related impairments of EF.
Each patient had been evaluated in a two hour clinical
interview by a licensed clinical ps ychologis t exper ienced
in assessing ADHD. During this interview the Brown
ADD Scale for Children or Adolescents [39,40] and
Story Memory Test of the Children’s Memory Scales [41]
or Logical Memory subtest of the Wechsler Memory
Scale-Third Edition [42] were administered. Diagnosis
of ADHD was made according to DSM-IV diagnostic
criteria. In a separate session the age-appropriate ve rsion
of the full Wechsler Intelligence Scale for Children -
Third or Fourth Edition [36,37], or the Wechsler Adult
Intelligence Scale-Third Edition [38] was administered
to each subject according to published guidelines.
Two index scores from the Wechsler IQ test, Working
Memory (WMI) and Processing Speed (PSI), were se-
lected to assess participants’ ability to hold in mind and
manipulate numerical information (WMI) and to scan
and output visual information under timed conditions
(PSI). In a sample of 678 children aged 6 to 16 years
diagnosed with ADHD, Mayes and Calhoun found that
these two index scores of the WISC-III/WISC-IV were
the most powerful predictors of academic impairment
[43]. Seidman has argued that these two index scores are
most likely to be impaired in adults with ADHD [44].
Rather than to compare group means on these mea s-
ures, this study compared each individual participant’s
WMI and PSI with the stronger of that individual’s VCI
or POI index scores on the Wechsler IQ test adminis-
tered. Kaufman and Lichtenberger [45] have recom-
mended a similar individual profile analysis approach as
a valid and useful way to compare the individual’s cog-
nitive strengths against measures of executive functions
necessary to deploy those strengths.
Working memory is not a unitary variable; different
working memory functions are associated with different
modalities and different types of information [28,29,46].
Often working memory is assessed with the Digit Span
test which is not always sensitive to impairments of
working memory for more complex verbal information.
Quinlan and Brown [26] demonstrated that ADHD
adults, in comparison to the general population, tend to
be impaired in their ability to recall two brief stories
immediately after hearing each one; that sample of
ADHD adults also showed greater impairment for recall
of the complex narrative content of the stories than on
recall of strings of digits, a component of the WAIS-III
Working Memory Index.
For this present study of children and adolescents w ith
both ADHD and high IQ, we asked each subject to listen
to each of the two age-appropriate stories of the Child-
ren’s Memory Scale [42] or the WMS-III Logical Mem-
ory subtest [43] and then scored their immediate recall
of each according to scoring guidelines described by
Quinlan and Brown [26]. The resulting score was then
transformed to an IQ-like score (mean of 100, SD of 15)
which was then subtracted from that individual’s VCI
index score on the Wechsler IQ test. In this way we cor-
rected for the correlation between overall verbal ability
and the person’s recall of the stories. This correction is
necessary because the national standardization sample
for the WMS-III [43] found a .58 correlation between
immediate auditory memory and Verbal IQ.
To obtain a more comprehensive measure of each par-
ticipant’s EF impairment in multiple activities of daily
life, the clinician administered the Brown ADD Scale
[33,34] orally to each parent (for children aged 6 to 11
years) or to the patient (for ages 12 to 17 years) during
the initial evaluation. This normed and validated scale
elicits parental report and/or self-report data regarding 5
clusters of ADHD-related EF. These include:
1) Organizing, prioritizing and activating to work
2) Focusing, sustaining and shifting attention to tasks
3) Regulating alertness, sustaining effort, and
processing speed
4) Managing frustra t ion and modulat i ng emotion s
5) Utilizing working memory and accessing recall
Rather than to merge data from all of these clusters
into one total score, we treated each cluster as a separate
item. This provided a more detailed profile of each sub-
ject’s reported level of EF impairment on each of these
five clusters.
With these data we determined each subject’s relative
impairment on standardized measures of 3 executive
functions: working memory, processing speed, and
short-term auditory verbal memory, and on 5 clusters of
executive functions assessed with the Brown ADD Scale
for Children [41] for ages 6 to 12 years or the Brown
ADD Scale for Adolescents [40] for ages 13 to 17 years,
normed and validated rating scales for ADHD-related

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
60
imp a i rments of executive functions in daily life.
2.3. Data Analysis
From the chart of each individual entered in this study,
we extracted scores for the three standardized measures
and the 5 clusters of self-report data described above.
This yielded 8 different measures of EF. For each meas-
ure we had defined a specific cut score to be taken as
indication of significant impairment and a higher cut
score to serve as a marker of severe impairment.
Each patient’s Wechsler I Q test index score for Verbal
Comprehension (VCI) or Perceptual Organization (POI)
(whichever was higher) was compared against his index
scores for working memory (WMI) and processing
speed (PSI) on the same test. An index score for working
memory or processing speed 1 SD (15 points or more)
lower than that individual’s VCI or PSI was considered a
marker for significant impairment; 2 SD was considered
a marker for severe impairment.
Each patient’s score on the standardized story memory
test (Children’s Memory Scale or Logical Memory sub-
test from the WMS-III) was compared with his VCI. A
story memory score 1 SD (15 points or more) lower than
that individual’s VCI was considered a marker for sig-
nificant impairment; 2 SD was taken as indicating severe
imp a i rment.
Each patient’s cluster scores on the Brown ADD
Scales were compared with the scale’s published norms
for that age group to determine degree of impairment
reported for that specific cluster of ADHD-related EF. A
T- Score of 65 or greater, 1.5 SD above the mean, was
taken as indicative of significan t impair ment.
Results were calculated in two ways. First, we deter-
mined how many of our 8 EF measures were impaired in
each of these high IQ participants with ADHD. While
we did not expect that each individual would be im-
paired on every one of these measures, we predicted that
most would be impaired on 5 or more of the eight meas-
ures.
Our second analysis of the data involved comparisons
between the percentage of our high IQ participants with
ADHD scoring in the impaired range on each of our 8
measures of EF relative to percentage rates of compara-
ble impairment in standardization groups for the respec-
tive measures. For the two index scores from the
WISC-III/IV and WAIS-III published data allowed us to
compare with general population norms for the same age
in the same IQ range, ≥120. Use of these norms provided
an answer to the question of whether discrepancies ob-
tained between verbal comprehension and or perceptual
reasoning index scores vs. working memory and
processing speed index scores are attributable to ADHD
or are found in the general population of children in this
age group who score in the superior range of IQ.
For the Children’s Memory Scale and the WMS-III
story memory task and the Brown ADD Scale for Child-
ren and the Brown ADD Scale for Adolescents, we used
age-based norms for the general population because
separate norms for those with superior IQ were not
available.
To assess the ADHD participants’ rate of significant or
extreme impairment on the eight measures of executive
function, Chi-square tests were calculated by using the
rate found in the standardization samples as the expected
value and the observed rate in the ADHD sample as the
observed value. This method was chosen because the
number of participants in the various standardization
samples was larger than our sample, and was different in
number from one measure to the other.
3. RESULTS
All patients in this study were selected because they
demonstrated cognitive strengths on verbal and/or per-
ceptual factors of the Wechsler IQ tests that placed them
in the top 9% of their age group in the general popula-
tion. Significant impairment on the Working Memory
Index was found in over 74% while severe impairment
was found in 40% (Figure 1). Processing Speed Index
was significantly impaired in over 80% and was severely
impaired in more than 42% (Figure 2).
Figure 3 shows that over 88% showed significant
impairment on their Story Memory Index relative to
their high Verbal Comprehension Index on the Wechsler
IQ test while over 37% were severely impaired. Analy-
sisof each patient’s scores on the Brown ADD Scale in
dicated that more than 64% of patients had significant
Figure 1. Percentage of high IQ participants significantly im-
paired or severely impaired on working memory index vs. VCI
or PRI with comparison to typically developing high IQ stu-
dents.

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
61
Figure 2. Percentage of high IQ participants significantly im-
paired or severely impaired on processing speed index vs. VCI
or PRI with comparison to typically developing high IQ stu-
dents.
Figure 3. Percentage of high IQ participants significantly im-
paired or severely impaired on story memory index vs. VCI
with comparison to typically developing students
reported impairment on at least 4 of 5 clusters of symp-
toms on the Brown ADD Scale (Figure 4).
Figures 1-4 also show the percentage of individuals
within similar age groups in the general population who
score at similar levels of impairment, as reflected in
published norms for these measures. For the two Wech-
sler IQ test index scores, comparisons are with others
whose IQ was ≥120. For scores on the Children’s Mem-
ory Scale, WMS-III Logical Memory and the Brown
ADD Scales, comparisons were made to the general
population of children sampled for published age norms
of those specific measures.
Figure 4. Percentage of high IQ participants with T-scores ≥ 65
on clusters of the Brown ADD Scale with comparison to typi-
cally developing students.
On all 8 measures of EF assessed in this study, the
percentage of patients impaired was very significantly
greater than percentage impaired in relevant standardiza-
tion samples for these measures (Figure 1-4). Tab le s 1
and 2 show that each of the eight chi-square values was
significant at (p < 0.001). Even with correction for
number of tests, the occurrence of EF disruption was
significantly greater in the ADHD samples than in the
standardization samples.
Moreover, despite their high IQ, 62% of these very
bright children and adolescents showed significant im-
pairment in 5 or more of the 8 markers of EF impairment.
These multiple measures converge to indicate that this
sample of youths with ADHD and high IQ showed sig-
nificant impairment on multiple measures of EF, despite
high IQ
4. DISCUSSION
These data provide evidence that among children and
adolescents with high IQ are some who fully meet
DSM-IV diagnostic criteria for ADHD. This study can-
not provide any estimate of what percentage of persons
with high IQ have ADHD, but it clearly demonstrates
that having high IQ does not preclude the possibility that
one might have ADHD.
We found strong support for the hypothesis that
youths with high IQ who meet diagnostic criteria for
ADHD tend to have significant weaknesses in working
memory, processing speed, and auditory verbal working
memory relative to their own cognitive ab ilities and that
they tend to report more impairments in executive func
tions (EF) than are reported for a comparable age group
in the general population. While some of these relative
imp a i rments may be within the average range of scores
on an absolute scale, they represent significant difficul-
ties for these very bright individuals who tend to have
great difficulty in achieving at the academic level gener-
ally expected from those with such high overall cogni-
tive abilities. Our analysis of the percentage of individ u-

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
62
Table 1. Expected vs. obtained numbers of participants scoring ≥1 or 2 SD on cognitive tasks.*Chi-Square (df = 1) all p < 0.001.
Variable Number+ Number– Expected+ Expected– Chi-Square
(corrected)*
Working Memory
Index 1SD 87 30 43 74 67.99
2SD 47 70 6 111 158.81
Processing Speed
Index 1SD 94 23 31 86 168.48
2SD 49 68 10 107 157.90
Story Memory
Index 1SD 103 14 29 88 244.32
2SD
44
73
3
11 4
547.37
Table 2. Expected vs. obtained numbers of participants scoring t = ≥ 65 on BADDS. *Chi-Square (df = 1) all p < 0.001.
BADDS clusters Number + Number – Expected + Expected –
Chi-Square
(Corrected)*
Activation
88
29
7
11 0
972.47
Focus
75
42
10
107
447.88
Effort 77 40 7 11 0 723.42
Emotion
42
75
10
107
105.08
Memory
77
40
7
11 0
723.42
als with these impairments may be a more useful meas-
ure for clinicians than group means because group
means tend to submerge individual variabilities.
Data in this study regarding impairments of auditory
verbal memory in youths with ADHD are fully consis-
tent with findings from the study by Quinlan and Brown
[26] of 176 adults with ADHD whose IQ scores spanned
the full normal range. This suggests that that children
and adolescents with high IQ diagnosed with ADHD
suffer from similar impairments of executive function, at
least for auditory verbal memory, as do adults with
ADHD on the wider spectrum of IQ scores.
Our findings in this study of children and adolescents
with high IQ are fully consistent with those of our pre-
viously published study of 157 adults with high IQ and
ADHD in which the same measures and methods were
utilized [47]. High IQ clearly does not protect individu-
als in childhood, adolescence or adulthood from having
impairments of ADHD.
Despite the elevated percentages of high IQ youths
with ADHD impaired on these measures, the measures
used in this study cannot be considered sufficient, singly
or in combination, to make or rule out a diagnosis of
ADHD. There are some with ADHD and high IQ who
are not significantly impaired on these measures, and
there are some impaired on these measures who do not
qualify for a diagnosis of ADHD. Yet these measures,
when combined with adequate clinical interview data
and additional relevant information, may provide useful
evidence to assist in identifying youths suffering from
EF impairments of ADHD, particularly those w hos e high
IQ may make their ADHD impairments more difficult to
recognize.
Clinical interviews w ith these youths and their par ents
indicated that children and adolescents with high IQ who
have ADHD may be at increased risk of having recogni-
tion and treatment of their ADHD symptoms delayed
until relatively late in their educational careers because
teachers and parents tend to blame the student’s disap-
pointing academic performance on boredom or laziness.
Many parents of these high IQ youths reported that
situational variability of their offspring’s inattention
symptoms was the primary reason for their ADHD im-
pairments not being recognized earlier. Like most others
with ADHD, these individuals all have a few specific
domains in which they have always been able to focus
very well, e.g. sports, computer games, artistic or musi-
cal pursuits, reading self-selected materials, etc. Parents
and teachers tended to assume that these very bright
children, could focus on any other tasks equally well, if
only they chose to do so [8].
Many parents also reported that their bright offspring
with ADHD often demonstrated considerable prowess in
performing specific tasks in which they had little posi-
tive personal interest, when they experienced considera-
ble fear of immediate negative consequences if they did
not complete that particular task by some imminent
deadline. Adolescent patients often described this as a
character trait, “I’m just a severe procrastinator” or “I
always work be s t u nder pressure.”

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
63
Doing well at tasks in which one has strong personal
interest, and being unable to begin a task until the very
last minute when a harsh deadline immediately looms,
are characteristics found in most individuals with ADHD
[8], but such traits can be especially problematic for high
IQ individuals with ADHD. When these very bright in-
dividuals with ADHD often do very well on tasks they
enjoy and/or when they are seriously “under the gun,”
those who know them are especially likely to see their
ADHD impairments in other situations as under volun-
tary control.
The assumption that such self-management can readi-
ly be shaped by conscious intentions is being challenged
by a number of studies demonstrating that cognitive
self-control tends to operate in an extremely rapid, au-
tomatized manner, largely under the influence of less
conscious emotional and cognitive motivational
processes [48-50]. Research is needed to test how these
automatized processes are related to executive function
impairments associated with ADHD.
For most of these high IQ youths with ADHD, it was
not until relatively late in their school years that their EF
impairments significantly interfered with their ability to
perform well. During early school years, many had been
placed in special classes or programs for talented and
gifted students, only to be removed eventually from
these programs as they failed to keep up with work re-
quirements in these more demanding classes. For many,
such failures and loss of status caused escalating demo-
ralization as they progressed through their elementary
and secon da r y s c hooling.
A number of the high IQ adolescent students in this
study were not evaluated for ADHD until their high
school years. Half of our sample were 16 or 17 years old
at the time of their first evaluation. Many of these stu-
dents reported that during elementary school years they
were able to function in ways that lived up to high ex-
pectations for academic success that were held by their
parents, their teachers and themselves. As was found in
the study of Langberg, et al., [51], it was in secondary
school settings where they had to keep track of various
homework assignments for many different teachers,
without anyone to help them to prioritize and reme mb er,
that ADHD impairments of these individuals became
apparent.
Some might question the validity of an ADHD diag-
nosis for individuals who do not manifest symptoms of
the disorder before age 7 years as stipulated by the
DSM-IV. Yet Faraone and colleagues [52] have demon-
strated that adults whose ADHD does not become ap-
parent until well past the DSM-IV stipulated age of on-
set at 7 years do not differ in functional impairment,
psychiatric comorbidity or family transmission of
ADHD when compared to adults whose ADHD symp-
toms were apparent by age 7. High IQ individuals with
ADHD may be at particular risk of protracted delays in
having their ADHD impairments recognized, evaluated
and treated, during which time they are likely to be
blam e d and p u nished for their ADHD impairments.
To our knowledge, this is, thus far, the largest sample
of high IQ children and adolescents with ADHD in the
published literature and the only one that utilized full IQ
tests. Our sample includes a wide range of ages, from 6
years to 17 years, a range over which progressive de-
velopment of EF is expected. It should be noted, howev-
er, that each measure used in the study utilized
age-corrected norms, thus each participant was com-
pared with others of the same age and, in the case of the
IQ index scores, others of the same age and with the
same high level of IQ.
5. CONCLUSIONS
This study demonstrates that individuals with high IQ
can fully meet DSM-IV diagnostic criteria for ADHD
and that they tend to suffer significant impairments on
executive functions measured by three standardized tests
and five separate clusters of a normed self-report scale.
Our data are reported in percentages of participants
who scored above or below the stipulated score
cut-points. We believe that such a presentation provides
information that may be more useful to clinicians as-
sessing individual children and adolescents than would
be group means which may submerge individual differ-
ences.
Limitations of the study
One limitation of this study is that comparisons were
made with published age-based norms for the measures
used rather than with a matched set of high IQ youths
who did not have ADHD. Our data on discrepancies
between IQ index scores, however, were compared with
national, population-based norms for matched age
groups with IQ in the same high range as our sample.
Comparisons for our other measures of EF were to
age-based normative samples of youths in the general
population, not specifically in the same range of IQ.
Despite these limitations, this study can serve to alert
educators and clinicians to the fact that some children
and adolescents with high IQ suffer from ADHD and
that their ADHD-related EF impairments can readily be
assessed with measures used in this study. Clinicians
evaluating high IQ children and adolescents who are
underachieving should consider ADHD as a possible
diagnosis and utilize appropriate measures to assess re-
lated EF impairments. This study also adds to the accu-
mulating data to demonstrate that general intelligence is

T. E. Brown et al. / Open Journal of Psychiatry 1 (2011) 56-65
64
not the same as executive functions; these are separate
aspects of integrated cognitive operations which should
be evaluated separately.
Competing interests
Dr. Brown is a consultant for Eli Lilly and Shire; he
has received research support from Eli Lilly and Shire
and receives royalties from The Psychological Corpora-
tion, American Psychiatric Press and Yale University
Press. The other authors declare that they have no com-
peting interests.
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