Psychiatry Research 258 (2017) 255–261

Contents lists available at ScienceDirect

Psychiatry Research
journal homepage: www.elsevier.com/locate/psychres

Five factor model personality traits relate to adult attention-deficit/ MARK

hyperactivity disorder but not to their distinct neurocognitive profiles
⁎
Fiona E. Van Dijka, , Jeannette Mostertb, Jeffrey Glennonc, Marten Onninkb, Janneke Dammersb,
Alejandro Arias Vasquezb,c,d, Cornelis Kand, Robbert Jan Verkesd, Martine Hoogmanb,
Barbara Frankeb,d, Jan K. Buitelaarc
a
Faculty of Social Sciences, Radboud University, Nijmegen, The Netherlands
b
Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
c
Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
d
Department of Psychiatry, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands

A R T I C L E I N F O A B S T R A C T

Keywords: Deficits in multiple neuropsychological domains and specific personality profiles have been observed in atten-
Adult ADHD tion-deficit/hyperactivity disorder (ADHD). In this study we investigated whether personality traits are related
Cognition to neurocognitive profiles in adults with ADHD. Neuropsychological performance and Five Factor Model (FFM)
Profiling personality traits were measured in adults with ADHD (n = 133) and healthy controls (n = 132). Three neu-
Inattention
ropsychological profiles, derived from previous community detection analyses, were investigated for personality
Inhibition
trait differences. Irrespective of cognitive profile, participants with ADHD showed significantly higher
Big Five
Openness Neuroticism and lower Extraversion, Agreeableness, and Conscientiousness than healthy controls. Only the FFM
Neuroticism personality factor Openness differed significantly between the three profiles. Higher Openness was more
Agreeableness common in those with aberrant attention and inhibition than those with increased delay discounting and aty-
Extraversion pical working memory / verbal fluency. The results suggest that the personality trait Openness, but not any other
Conscientiousness FFM factor, is linked to neurocognitive profiles in ADHD. ADHD symptoms rather than profiles of cognitive
impairment have associations with personality traits.

1. Introduction individuals with ADHD based on a similar neurocognitive profile, both

in children and in adults (Fair et al., 2012; Mostert et al., 2015a; van
Attention-deficit/hyperactivity disorder (ADHD) is a common neu- Hulst et al., 2015). Such results provide some structure to the hetero-
ropsychiatric disorder that is characterized by symptoms of inattention, geneity in ADHD. However, the clinical utility of subgrouping based on
hyperactivity, and impulsivity. ADHD often persists into adulthood neuropsychological characteristics in ADHD needs to be explored.
(Faraone et al., 2015). Current research does not support a single core Contributing to the heterogeneity of ADHD is the presence of tem-
(neuro)cognitive deficit of ADHD, but rather demonstrate that both perament and personality traits. Temperament traits can be described
childhood and adult ADHD are characterized by strong heterogeneity in as a set of biologically based behavioral and emotional tendencies
cognitive underperformance with multiple cognitive pathways covering negative and positive emotion systems as well as attentional
(Sonuga-Barke et al., 2010; De Zeeuw et al., 2012; Fair et al., 2012; capacities (Rothbart, 2011). A recent study clustered children with
Coghill et al., 2014b; Mostert et al., 2015b). The main domains of ADHD into subgroups based on temperament dimensions of the Tem-
neuropsychological dysfunction in ADHD are: memory, inhibitory perament in Middle Childhood Questionnaire. The results suggested
control, delay aversion, decision making, timing, and response varia- three novel types of ADHD that were independent of existing clinical
bility. The levels of deficiency in each of these domains differ more or demarcations, including DSM-5 presentations (Karalunas et al., 2014).
less independently within patients with ADHD, and there is consider- Type 1, the mild type, had milder impulsivity, inhibition, and atten-
able overlap between neuropsychological performance in patients with tional control impairments compared with the other two ADHD types.
ADHD and normal controls (Coghill et al., 2014b). Use of multivariate Type 2, the surgent type, had increased impulsivity, activity levels and
classification techniques has led to the identification of subgroups of assertiveness, decreased shyness coupled to high intensity pleasure

⁎
Corresponding author.
E-mail address: fevandijk@gmail.com (F.E. Van Dijk).

http://dx.doi.org/10.1016/j.psychres.2017.08.037
Received 7 October 2016; Received in revised form 14 February 2017; Accepted 16 August 2017
Available online 19 August 2017
0165-1781/ © 2017 Elsevier B.V. All rights reserved.
F.E. Van Dijk et al. Psychiatry Research 258 (2017) 255–261

seeking than the other two types. Type 3, the irritable type, had in- (a facet of Openness) were positively associated with verbal fluency,
creased impulsivity and attentional control impairments than type 1 indicating that ‘ideas’ may be a key characteristic in the association
and increased negative emotionality compared to the other two types. between Openness and cognition. Those open to ideas are likely to
Personality research in general has mostly used the Five Factor Model spend more time exploring intellectual pursuits, which could translate
(FFM) (Costa and McCrae, 1992) as a well-supported organizing fra- into a greater facility with words. Extraversion (trait) and ‘assertive-
mework that has been characterized with respect to underlying tem- ness’ (a facet of Extraversion) were negatively related to reasoning and
perament dimensions (i.e. the initial state of emotional, motor, and reaction time, indicating that extraverted individuals may be faster, but
attentional reactivity from which personality develops in interaction are less likely to take time to think thoroughly about a task. The FFM
with experience) (Rothbart, 2007). The five factors are Neuroticism, traits and their facets did not predict working memory or episodic
Extraversion, Agreeableness, Conscientiousness, and Openness. Briefly, memory in this study. The association between Neuroticism and cog-
Neuroticism is the predisposition to experience psychological stress in nitive performance was found primarily among younger adults. In older
the form of anxiety, anger, depression or other negative affect. Extra- adulthood, better performance was associated with positive emotional
version refers not only to sociability but also to liveliness and cheer- aspects of personality (positive emotions (Extraversion)) and Openness
fulness. Agreeableness involves trust, altruism and sympathy. Con- to feelings (Graham and Lachman, 2014).
scientiousness encompasses both a disciplined striving after goals and So far, the studies of cognitive performance and personality did not
strict adherence to principles, whereas Openness is seen in aesthetic take the presence of psychopathology into account. In the present
sensitivity, intellectual curiosity, need for variety, and nondogmatic study, we follow-up on this previous work regarding the subtyping of
attitudes. A recent review of findings on ADHD and FFM personality ADHD by cognition and temperament. Specifically, we examined,
suggests that, in general, ADHD has associations with the FFM traits of whether adults with ADHD and healthy controls, who share similar
Neuroticism (positive), Agreeableness (negative) and Conscientiousness neurocognitive profiles, also share specific personality traits, or, alter-
(negative). Mixed findings (positive, negative, and no associations) natively, whether ADHD is related to personality irrespective of a
have been reported for Extraversion and Openness (Gomez and Corr, specific neurocognitive profile. To this end, we built on our earlier
2014). work, in which we had identified by community detection analysis
Prior research, mostly assessing the relationship between single three subgroups of patients and healthy controls based on cognitive
tasks or facets of executive function and single FFM traits in healthy profiles. Community detection is a technique based on graph theory to
participants, suggests that significant associations also exist between identify clusters within networks of participants that are highly corre-
FFM traits and neurocognitive functioning, especially executive func- lated with each other, and marginally correlated with participants from
tioning (for an overview, see (Williams et al., 2009)). Three more recent other clusters (Newman, 2006). In this case the network represents
studies extended that early research by considering all five FFM traits in correlations between individuals in terms of neuropsychological per-
relation to a more fully characterized domain of executive functioning. formance. The three subgroups were characterized by (1) poor perfor-
A first study among 58 healthy older (mean age 70 years) adults in- mance on attention and inhibition, (2) high scores for impulsive be-
vestigated four tests assessing all core aspects of executive functioning havior on the delay-discounting task (delay aversion), (3) impairment
(cognitive flexibility, initiation, inhibition, response selection, working on working memory and verbal fluency (Mostert et al., 2015a). Given
memory, generative fluency, and attentional vigilance) (Williams et al., the recent evidence for the relationship between executive functions
2010). The results showed that the executive functioning factor, that and FFM trait outcome as outlined above, we anticipated that our
emerged from four executive functioning scores (one for each executive previously identified profiles 1 and 3 would be associated with higher
functioning test), was negatively correlated with Neuroticism and po- Neuroticism and lower Openness. Further, in keeping with previously
sitively with Openness and Agreeableness. But although high Neuroti- found associations between Extraversion and higher delay aversion
cism was associated with poorer executive functioning, both the middle rates (Hirsh et al., 2008), we also anticipated that Extraversion would
and high executive functioning groups were in the average range for be positively related to our cognitive profile 2. Alternatively, if it would
Neuroticism (compared to normative values). Individuals with better be the ADHD symptoms that accounted for FFM trait outcome rather
executive functioning were characterized by high Openness and than the cognitive profiles, we expected to find associations of the FFM
Agreeableness and average levels of Neuroticism. Executive functioning traits with diagnostic group, irrespective of cognitive profile member-
was not associated with Extraversion or Conscientiousness in this study. ship. Such associations could be expected for Neuroticism, Con-
A second study, including 182 students, examined three separate scientiousness, and Agreeableness. The results can add to the under-
core executive function factors (i.e. inhibition, updating/monitoring standing of the associations between FFM traits and executive
information in working memory, and cognitive flexibility) as predictors functioning, in particular in an adult ADHD population.
of the five FFM traits (Murdock et al., 2013). Higher Neuroticism and
lower Openness were associated with poor updating/monitoring, and 2. Methods
Openness was positively associated with cognitive flexibility (the
ability to shift one's attention between multiple tasks or mental sets). 2.1. Participants
The authors suggested that Neuroticism and Openness may share some
common underlying cognitive mechanism, in particular working A total of 265 participants (133 adults with ADHD and 132 healthy
memory. Connections between executive functioning and Extraversion, controls) between 18 and 65 years old were included in this study. All
Agreeableness, and Conscientiousness did not emerge in this study. participants were part of the Dutch node of the International
A third study examined associations between FFM traits and cog- Multicentre persistent ADHD Collaboration (IMpACT – http://
nitive performance to 1) uncover the specific facets of each trait that are impactadhdgenomics.com (Franke et al., 2010)). Participants had
most closely related to cognition, and 2) examine, how these associa- been recruited from the Department of Psychiatry of the Radboud
tions may vary by age in 154 healthy older and younger adults (age University Medical Center (RadboudUMC) in Nijmegen and through
22–84). The cognitive domains measured were processing speed, re- advertisements. Patients were included if they had previously been
action time, verbal fluency, inductive reasoning, and working and diagnosed with adult ADHD by a psychiatrist according to the Diag-
episodic memory. Neuroticism (trait) and in particular ‘depression’ (a nostic and Statistical Manual of Mental Disorders (4th edition; DSM-IV-
facet of Neuroticism) were negatively associated with performance on TR; American Psychiatric Association, 2000). Exclusion criteria were
cognitive tasks that require effortful processing. The results suggested psychosis, alcohol, or substance addiction in the last six months, current
that individuals, who are more angry and depressed, have slower pro- major depression, full-scale IQ estimate < 70, neurological disorders,
cessing speed and lower reasoning scores. Openness (trait) and ‘ideas’ sensorimotor disabilities, non-Caucasian ethnicity, and medication use

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other than psychostimulants, atomoxetine, or bupropion. Additional The ADHD and the control group each separated into three profiles that
exclusion criteria for healthy participants were a current or lifetime differed in cognitive performance. Profile 1 was characterized by
neurological or psychiatric disorder in either the participant or his/her aberrant attention and inhibition, profile 2 by increased delay dis-
first-degree relatives. counting, and profile 3 by atypical working memory and verbal fluency.
The same profiles were observed in the control and ADHD sample.
2.2. Ethical standards Details about the method, sample sizes, results are described in (Mostert
et al., 2015a).
This study was approved by the regional ethics committee (Centrale
Commissie Mensgebonden Onderzoek: CMO Regio Arnhem – Nijmegen; 2.6. Five factor model personality measurement
Protocol number III.04.0403). Written informed consent was obtained
from all participants. The authors assert that all procedures con- The participants completed the NEO-FFI (Costa and McCrae, 1992),
tributing to this work complied with the ethical standards of the re- a 60 item self-report assessing each of the 5 FFM personality domains:
levant national and international and institutional committees on Extraversion, Agreeableness, Conscientiousness, Neuroticism, and
human experimentation and with the Helsinki Declaration of 1975, as Openness to experiences. Each domain includes 12 items. The NEO-FFI
revised in 2008. was not intended to provide definitive measurement of the five per-
sonality factors, but was designed as a brief instrument that would yield
2.3. Psychiatric assessment reasonable estimates of the factors, useful in exploratory research. In
over a decade of use, it has shown itself to be reliable, valid, and useful
Both patients and controls were assessed using the structured di- in a variety of contexts and cultures (McCrae and Costa, 2004). Extra-
agnostic interview for adult ADHD (DIVA 2.0.; www.divacenter.eu version reflects being sociable, outgoing, optimistic, sensation seeking,
(Kooij, 2010)). This interview focuses on the 18 DSM-IV symptoms of and talkativeness. Agreeableness refers to the tendency to be agreeable,
ADHD and uses concrete and realistic examples to thoroughly in- trustworthy, friendly, and cooperative with others, rather than suspi-
vestigate whether a symptom is currently present or was present in cious and antagonistic towards others. It is also a measure of whether a
childhood. Additionally, a self-report questionnaire on current symp- person is generally well tempered or not. Conscientiousness reflects a
toms was obtained using the ADHD Rating Scale-IV (Kooij et al., 2005). person's tendency to be well organized, responsible, and task-focused in
Lifetime DSM IV axis I and II disorders were assessed with the Struc- pursuing goals. Neuroticism indicates the tendency for proneness to
tured Clinical Interview for DSM disorders I and II (SCID I and SCID II) unpleasant experience, such as anger, anxiety, depression, and mal-
(Groenestijn et al., 1999; Weertman et al., 2000). With regard to the adjustment. Neuroticism also refers to the degree of emotional stability
Axis II personality disorders, participants first filled out the SCID II self- and impulse control and is sometimes referred to by its low pole,
report questionnaire, and when applicable, according to the SCID II "emotional stability". Openness to experience reflects a person's ten-
manual, the clinical interview followed. Further measurements in- dency for being imaginative, creative, and interested in cultural and
cluded an MRI scanning session and blood withdrawal for DNA ana- educational experiences.
lysis. These data are described elsewhere and are not part of the current
analyses (Franke et al., 2008, 2010; Hoogman et al., 2011, 2013; 2.7. Statistical analysis
Onnink et al., 2014).
In the current study, we tested for FFM trait differences between the
2.4. Neuropsychological testing battery three neurocognitive profiles using analysis of variance (ANOVA). For
this, a two (group: ADHD vs. Control) by three (the cognitive profiles:
Neuropsychological performance was measured using a test battery inattention and inhibition [profile 1] vs. delay aversion [profile 2] vs.
that included measures tapping into executive functioning (working working memory and verbal fluency [profile 3]) ANOVA was per-
memory, attention, inhibition, set-shifting, fluency) and delay dis- formed on the scores of each of the five factors of the FFM, with group
counting, deficits of which have been earlier reported in ADHD. Details and cognitive profile as between-subject factors and the FFM factors as
about tasks and main outcome measures are described in dependent variables. These calculations were done using SPSS (version
Supplementary Table 1 and our previous reports (Mostert et al., 2015a, 20; SPSS, Chicago, IL).
2015b). The tests were always administered in the same order. In total,
21 variables in seven tasks were analyzed. Outliers were defined as 3. Results
having a score higher than four times the standard deviation above or
below the mean per group (Leth-Steensen et al., 2000; Nigg et al., Demographics of the sample are described in Table 1. Adults with
2005). This threshold guarded against artefacts, while still including ADHD and healthy controls did not differ in age, gender, or IQ, but
cases performing at the extreme of the normal distribution (i.e., in- controls had a higher level of education. Table 2 presents the scores
cluding low performing cases that might have more severe ADHD (mean and SD) of all six groups analyzed in the ANOVA on all factors of
symptoms). If a participant's score was an outlier on one outcome the FFM.
variable of a task, his/her scores on all outcome variables from that task The analyses of the Neuroticism scale did not reveal a main effect of
were excluded. All data was transformed in such a way that higher cognitive profile (F(2, 246) = 0.26, p = 0.77), but a main effect of
values indicated worse performance. To estimate IQ, subtests of the diagnostic status was observed, with a significantly higher score on
Wechsler Adult Intelligence Scale (WAIS-III) were administered (voca- Neuroticism for the ADHD than the control group (F(1, 246) = 124.09,
bulary and block design) (Wechsler, 1997). p = 0.0001). Furthermore, the interaction effect of group and cognitive
profile was significant (F(2, 246) = 4.25, p = 0.02). Using a one-way
2.5. Neurocognitive profiles ANOVA to localize this effect revealed no significant differences be-
tween any of the profile groups for the ADHD-group (F(2, 121) = 1.18,
In our previous report, Confirmatory Factor Analysis (CFA) was p = 0.31), whereas the same analysis on the control group yielded a
used to reduce neurocognitive data to six cognitive factors: reaction significant main effect, F(2, 125) = 3.50, p = 0.03. However, post-hoc
time and variability, delay discounting, verbal fluency, working comparisons revealed that none of the differences survived Bonferroni
memory, attention and inhibition. Subsequently, factor scores were correction. In effect, the two groups did not differ on the cognitive
correlated across subjects to form networks. Further, a community de- profiles.
tection algorithm was used to cluster these networks into subgroups. On the Extraversion scale a main effect of group was found (F(1,

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Table 1 controls or are related to ADHD irrespective of a specific neurocognitive

Demographics of the participants. profile. Our main findings are: 1) that there is no relationship between
personality traits and cognitive profiles for most FFM traits; 2) that a
ADHD Healthy Statistics
patients controls relationship between Openness to experience and inattention / disin-
(N = 133) (N = 132) hibition is observed; 3) that we can confirm a relationship between
ADHD and personality traits.
Gender M/F 56/77 53/79 χ2 (1, N = 265) = 0.10,
Irrespective of cognitive profile, participants with ADHD were
p = 0.75
Age Mean (SD) 35.56 (10.40) 36.30 (11.75) t(258,7) = 0.54, p = found to have higher scores for Neuroticism and lower scores for
0.59 Extraversion, Agreeableness, and Conscientiousness than healthy con-
a
IQ Mean (SD) 107.84 109.97 (14.90) t(263) = 1.19, p = 0.24 trols. Cognitive profile was significantly related to Openness, which was
(14.34) higher in participants with profile 1 (inattention and disinhibition) than
Educationb Mean 4.70 (0.80) 5.16 (0.81) t(263) = 4.66,
in participants with one of the other two cognitive profiles (2 (delay
(SD) p < 0.001
aversion / impulsivity)) and 3 (working memory / verbal fluency) in
Because Levene’s test for equality of variances was significant in the t-test for the dif- both ADHD patients and controls. No additional associations between
ferences in ages, degrees of freedom were adjusted accordingly. FFM measures and cognitive profiles were found. Previously, it has
a
Estimated IQ based on performance on the WAIS-III block pattern and vocabulary been proposed that ADHD originates from a primary cognitive deficit in
tasks.
b a specific executive functioning (EF) domain such as response inhibi-
Education levels were coded from 1 (unfinished primary school) to 7 (post-uni-
versity). tion or working memory or a more general weakness in executive
control (Pennington and Ozonoff, 1996; Barkley, 1997; Schachar et al.,
Table 2
2000; Castellanos and Tannock, 2002). The current study demonstrates
Outcome of Five Factor Model traits for the ADHD and healthy control groups in Profile 1, that personality, as measured with the NEO-FFI, and cognitive perfor-
2, and 3. mance are mainly separate domains that apparently do not share si-
milar etiological factors or underlying mechanisms in adult ADHD. Our
Profile 1 (N=98; Profile 2 (N=62; Profile 3 (N=105;
study also documents that personality may be more closely related to
53% ADHD) 50% ADHD) 48% ADHD)
clinical symptoms than the cognitive profiles. Treating the cognitive
ADHD HC ADHD HC (SD) ADHD HC domains may therefore not necessarily be the most useful therapeutic
(SD) (SD) (SD) (SD) (SD) approach in ADHD. However, the cognitive profiles may be more clo-
Neuroticism 39.8 24.0 36.9 28.3 38 (6.8) 27.4
sely related to functional impairments (Mostert et al., 2015a). In any
(8.9) (7.1) (9.8) (10.1) (6.7)
Extraversion 41.7 44.6 40.1 42.1 40.9 42.9 case, it seems important to look at other factors such as personality
(7.4) (6.2) (6.7) (6.5) (6.7) (4.5) beyond cognition in considering what are the most clinically useful
Openness 43.6 41.6 38.4 39.5 41 (5.4) 38.9 options for patient management. Although this aspect was outside the
(6.1) (4.8) (6.8) (5.1) (5.5) scope of the current study, it would be useful to know if patient stra-
Agreeableness 42.8 46.2 40.7 46.2 43.6 46.7
(5.7) (6.2) (6.7) (5.4) (5.4) (4.5)
tification on personality profile could inform treatment response.
Conscientiousness 34 (6.4) 44.9 35.2 45.9 34.5 46.4 With regard to the relationship between personality and cognitive
(6.5) (6.2) (5.3) (6.5) (4.4) domains in ADHD, we only found a higher score on Openness to ex-
periences in participants with cognitive profile 1 (poor performance on
Profile 1: poor performance on attention and inhibition; Profile 2: high scores for im- attention and inhibition) than in participants with profiles 2 and 3.
pulsive behavior on the delay-discounting task (delay aversion); Profile 3: impairment on
Individuals high in Openness tend to be unconventional, explorative,
working memory and verbal fluency. HC = healthy control.
and interested in novelty. This could suggest that Openness is asso-
ciated with active and impulsive behavior and that disinhibition pos-
247) = 7.76, p = 0.006) with significantly higher scores for the healthy
sibly may underlie Openness. Such a relationship has been observed
control group. There was neither a main effect of cognitive profile (F(2,
before in a study in an adolescent male sample with high scores on
247) = 2.03, p = 0.13), nor an interaction effect of group and cognitive
aggression; while controlling for cognitive abilities an association of
profile (F(2, 247) = 0.15, p = 0.87).
Openness with externalizing behavior (i.e. aggression, opposition, and
The analysis of the Openness scale revealed a main effect of cog-
hyperactivity) was reported (Deyoung et al., 2008). Cognitive abilities
nitive profile (F(2, 247) = 9.10, p = 0.0001), showing that the parti-
were measured using the Block Design and Vocabulary subtests of the
cipants in profile 1 scored significantly higher than the participants in
Wechsler Intelligence Scales for Children and a working memory (or
profile 2 and profile 3. Effects of group and the interaction of group and
executive function) score derived from a battery of neuropsychological
cognitive profile were non-significant (F(1, 247) = 1.92, p = 0.17; F(2,
tasks assessing cognitive abilities associated with prefrontal cortex. In
247) = 1.76, p = 0.17).
that case, the variance in Openness was related to the FFM higher order
On the Agreeableness scale, a significant main effect of group was
meta-trait plasticity (i.e. the shared variance of Extraversion and
found, with significantly higher Agreeableness scores for the healthy
Openness, appearing to reflect the tendency to engage actively and
controls (F(1, 247) = 30.68, p = 0.0001). No effects of cognitive
flexibly, both behaviorally and cognitively with novelty – in other
profile (F(2, 247) = 1.71, p = 0.18) or the interaction of group and
words, to explore). Plasticity was positively associated with ex-
cognitive profile (F(2, 247) = 0.95, p = 0.39) were observed.
ternalizing behavior, whereas variance due to cognitive ability was
Lastly, there was a significant main effect of group on the
negatively associated with such behavior. The findings of that study
Conscientiousness scale, with significantly higher scores for the healthy
indicated that if one examines individuals equal in the other FFM
controls compared to the ADHD patients (F(1, 247) = 214.50, p =
higher order meta-trait stability (i.e. the shared variance of Neuroticism
0.0001). There was no significant main effect of cognitive profile (F(2,
reversed, Conscientiousness, and Agreeableness, reflecting stable func-
247) = 0.89, p = 0.41), and no interaction effect of group and cog-
tioning in emotional, motivational, and social domains) and cognitive
nitive profile were observed (F(2, 247) = 0.23, p = 0.80).
ability, those higher in behavioral plasticity are likely to show higher
levels of externalizing behavior. In our current study, this may under-
4. Discussion line the relatively higher Openness outcome in profile 1, since it is
characterized by inhibition deficits (as measured by a go/no go task).
The present research investigated, whether FFM traits are sig- Interestingly, when the number of self-reported hyperactivity/im-
nificantly related to neurocognitive profiles in adults with ADHD and pulsivity symptoms was examined in our previous study defining the

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cognitive profiles, those symptoms were shown to be unequally dis- relationship, touching upon the possibility that personality and psy-
tributed across the three cognitive profiles: The patients in profile 1 chopathology may themselves fail in some instances to be distinct en-
(and 2) had indeed significantly more hyperactivity/impulsivity tities. They may instead exist along a common spectrum of functioning.
symptoms than in profile 3 (Mostert et al., 2015a). While DeYoung et al. All personality disorders may in fact be maladaptive variants of general
also found a relationship between Extraversion and the cognitive pro- personality traits, and some personality disorders could be early onset,
files, we did not observe this link. chronic, and pervasive variants of other mental disorders. Finally, they
The finding that Openness is related to the neurocognitive profile can have a causal role in the development or etiology of one another.
associated with ADHD symptoms is intriguing. On the one hand, its Unfortunately, the current study cannot tell us, which of the three is
association with inattention and inhibition as measured with neuro- applicable to ADHD and personality, as it is a cross-sectional study in
cognitive tasks, and on the other hand the association of the profile adults. Moreover, it also suggests that personality and cognition are
with hyperactivity/impulsivity symptoms. This makes it plausible that independent entities without significant influence on each other. Future
impulsiveness and inattentiveness may result in Openness, which studies should therefore characterize, whether the NEO FFI personality
therefore might be viewed as disinhibition instead of a personality trait. profiles are related to innate temperament or behavioral responses. This
Earlier work proposed that Openness is likely to involve the prefrontal may clarify, whether the relationship between personality and ADHD is
cortex and functionally related regions, particularly those involved in based on latent temperamental aspects and/or the ability to behavio-
working memory, abstract reasoning, and the control of attention rally respond to changing internal and external cues.
(DeYoung et al., 2005). The conceptualization and understanding of the Another, more fundamental, question that arises from the conclu-
trait Openness clearly warrants further consideration. sion that neurocognitive profiles are not mediating between ADHD
The basis for the association found for Openness but not for symptoms and personality traits is what neurocognitive profiles really
Extraversion may also be related to the choice of instrument chosen for are? And perhaps even more important, why would we use cognitive
personality profiling, i.e. the NEO FFI. Within the literature, there is profiles if they cannot be generally related to clinical symptoms of
currently a debate over the basis of personality traits. Some emphasize ADHD or personality, and cannot predict treatment outcome? Could it
the phenotypical aspects of the FFM traits, whereas others emphasize be that neurocognitive performance is no more than just a snapshot,
the neurobiological bases of the FFM, such as cognition and affect. whereas the behavioral outcome may be dependent on one's motivation
Research on the levels of affects (A), behaviors (B) and cognitions (C) to perform at that particular moment? There are suggestions that ADHD
included within the operational definitions of each of the FFM traits has is not well characterized by deficits in neurocognitive functioning
been conducted. Openness within the NEO FFI inventory emphasizes (Mostert et al., 2015a, 2015b). It would therefore be of interest to in-
cognition and affect over behavior. Thus, the association we found vestigate the role of neurocognition in ADHD when coupled to different
between Openness and cognitive profile 1 may also simply reflect the motivations and contexts.
fact that poor attention and inhibition within profile 1 is in line with the Although we used data from a large sample of adults with persistent
used definition of cognition (i.e. thought, beliefs, patterns, or modes of ADHD and healthy controls, the interpretation of the results of our
thinking) in Openness. In contrast, for Extraversion (for which we have study should be viewed in the context of some limitations. Firstly, the
not seen a relationship with cognitive profiles), there is a striking lack neuropsychological measurements did not cover exactly the same
of cognitive content within its NEO FFI definition and instead a sub- cognitive domains that were used in other studies investigating links
stantial emphasis on its affective aspects (i.e. internal, motivational, between personality and cognitive performance. Secondly, we focused
and evaluative ‘valenced’ states including patterns of feelings, emo- on previously obtained cognitive profiles that were created using a
tions, and preferences) and some behavioral content (i.e. observable specific clustering method; different clustering methods may result in
actions, including both active and passive behaviors, but not including the creation of different cognitive profiles. Thirdly, we employed the
mental events) (Pytlik Zillig et al., 2002). Therefore, it is not surprising NEO FFI, which is the shortened version of the NEO-PI-R and not in-
that no relationship was found in this study between Extraversion and tended to replace the full NEO PI-R. As such, the NEO FFI measures a
cognitive profile. reduced range of constructs, which could be argued not to represent the
The finding that the presence of ADHD rather than cognitive profile full spectrum of personality profiles. Lastly, we want to address the
is associated with personality traits is in keeping with previous research possible role of gender. Although no gender differences between the
questioning the mediating role of cognition in ADHD. It is in line with two groups were found, the total sample included more women than
current thinking that the relationship between cognitive deficits and men. Previous research has demonstrated that women report them-
symptomatic aspects of ADHD is more complex than previously re- selves to be higher in Neuroticism, Agreeableness, warmth, and open-
cognized (Coghill et al., 2014a; Mostert et al., 2015a, 2015b). Indeed, ness to feelings, whereas men were higher in assertiveness and open-
we observed several direct links between personality and ADHD diag- ness to ideas (Costa et al., 2001). One study, focusing on a large group
nosis. More specifically, we noted lower Agreeableness, Con- of adult ADHD and control subjects found that in all female cases the
scientiousness and Extraversion and higher Neuroticism in the ADHD scores for Neuroticism, Extraversion, and Openness were higher in fe-
participants than in the controls, irrespective of cognitive profile and males than in males (Jacob et al., 2007). Our results seem to be much in
similar to previous findings on ADHD and personality (Jacob et al., line with these findings. Despite the limitations, our study confirms that
2007; Gomez and Corr, 2014). Previous work on ADHD and personality ADHD patients show different levels of personality traits compared to
traits concluded that ADHD in general is associated with 1) both in- controls.
ternalizing, and anxiety and depression related dimension of person-
ality (high outcome on Neuroticism) and 2) externalizing behavior (low 5. Conclusion
outcome on Agreeableness and Conscientiousness), which can be an
interesting starting point for further research in adult ADHD (Jacob Our study suggests that the presence of ADHD is strongly connected
et al., 2014). to personality traits, as four out of five factors of the FFM Model dif-
The implications of the lack of significant interactions between fered between ADHD patients and healthy controls. Moreover, a link
adult ADHD, cognitive profiles and personality deserve discussion. between personality and cognitive profile was observed for Openness.
Theoretically, personality and psychopathology can relate to one an- Openness was significantly related to a neurocognitive profile of poor
other in three different ways (Widiger, 2011). Personality and psy- performance on attention and inhibition tasks in ADHD patients as well
chopathology can influence the presentation or appearance of one an- as in healthy controls. In sum, our data suggest that personality and
other, commonly referred to as a pathoplastic relationship. They can cognitive performance are mainly separate domains that do not share
share a common, underlying etiology, referred to as a spectrum similar etiological factors or underlying mechanisms in ADHD.

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Conflict of interest Hyperactivity Disorder. Nat. Rev. Dis. Prim.

Franke, B., Hoogman, M., Arias Vasquez, A., Heister, J.G., Savelkoul, P.J., Naber, M.,
Scheffer, H., Kiemeney, L.A., Kan, C.C., Kooij, J.J., Buitelaar, J.K., 2008. Association
The authors report no conflicts of interest. Jan Buitelaar has been in of the dopamine transporter (SLC6A3/DAT1) gene 9-6 haplotype with adult ADHD.
the past 3 years a consultant to/member of advisory board of/and/or Am. J. Med. Genet. Part B, Neuropsychiatr. Genet. : Off. Publ. Int. Soc. Psychiatr.
Genet. 147B, 1576–1579.
speaker for Janssen Cilag BV, Eli Lilly, Shire, Novartis, Roche and Franke, B., Vasquez, A.A., Johansson, S., Hoogman, M., Romanos, J., Boreatti-Hummer,
Servier. He is not an employee of any of these companies, and not a A., Heine, M., Jacob, C.P., Lesch, K.P., Casas, M., Ribases, M., Bosch, R., Sanchez-
stock shareholder of any of these companies. He has no other financial Mora, C., Gomez-Barros, N., Fernandez-Castillo, N., Bayes, M., Halmoy, A., Halleland,
H., Landaas, E.T., Fasmer, O.B., Knappskog, P.M., Heister, A.J., Kiemeney, L.A.,
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Barbara Franke has received educational speaking fees from Merz and Haavik, J., Cormand, B., Ramos-Quiroga, J.A., Reif, A., 2010. Multicenter analysis of
Shire. Jeffrey Glennon has been in the past 3 years a consultant to the SLC6A3/DAT1 VNTR haplotype in persistent ADHD suggests differential in-
volvement of the gene in childhood and persistent ADHD. Neuropsychopharmacol. :
Boehringer Ingelheim on a topic not related to the content of this
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