Altered executive function in obesity. Exploration of the role of affective
states on cognitive abilities
Rena ´ta Cserje ´sia,b,*, Olivier Luminetb, Anne-Sophie Ponceletb, La ´szlo ´ Le ´na ´rda
aInstitute of Physiology and Neurophysiology Research Group of the HAS, Pe ´cs University, Medical School, Szigeti str. 12, H-7643 Pe ´cs, Hungary
bUnit Emotion, Cognition and Health, Faculty of Psychology, University of Louvain, Place Cardinal Mercier 10, B-1348 Louvain-la-Neuve, Belgium
between the inside world and environmental challenges, as
well as for adjusting human behaviour in a flexible way to
situations which require individuals to overcome a strong
habitual response or to resist temptation (Norman & Shallice,
1980/2000). Different executive functions may include: cogni-
tive control, the ability to sustain or flexibly redirect attention,
the inhibition of inappropriate behavioural responses, initiation
and execution of strategies, and the ability to flexibly switch
among strategies (Robbins, 1998). People with obesity report
that they feel they fail to resist food as a temptation and also
report difficulties in controling aspects of their own lives (Gionta,
1995). Indeed, there is a growing evidence that obesity is not
only an increased calorie intake and weight management
problem, but it is linked to adverse neurocognitive outcomes,
including reduced cognitive functioning, specifically frontal lobe
based executive functions (Gunstad et al., 2007). Consistent with
this notion and supporting the idea of a deficit of executive
function in obese individuals, obese children evidence more
impulsivity, lack of cognitive control, mental inflexibility and
perseverence (Braet, Claus, Verbeken, & van Vlierberghe, 2007;
Cserjesi, Luminet, Molnar, & Lenard, 2007). In adults, obesity was
associated with poorer cognitive performance, independently
from age and endocrinology factors, namely hypertension and
diabetes (Cournot et al., 2006; Elias, Elias, Sullivan, Wolf, &
D’Agostino, 2003). Apart from the cognitive dysfunctions, several
studies have shown that obesity and depression frequently are
linked together (Annunziato & Lowe, 2007; Friedman, Reich-
mann, Costanzo, & Musante, 2002). For the most part, obesity
and depression have been compartmentalized as a separate
health problem of physical and emotional natures. However,
depression and obesity have shared symptoms such as sleep
problems, changed appetite and dysregulated food intake
(Reeves, Postolache, & Snitker, 2008).
It has been also found that depressive status (both clinical and
subclinical) have a major impact on executive functions and on
sustained attention (Holmes & Pizzagalli, 2007; Weiland-Fiedler
et al.,2004). Denckla (1994) reported that
depression can mimic executive dysfunction, causing a sort of
disconnection in the frontal lobes based executive function from
other brain functions. Besides the several medical and psycho-
logical interests based studies, the relationship between obesity,
executive dysfunctions and depressive status has not yet been
Our main aim was to investigate how the possible cognitive
impairments on executive functions and emotional status, namely
depression, anxiety and positive versus negative affectivity relate
to adult obesity. We presume that executive function deficits in
obesity are mediated by the frequently reported negative
emotional status such as depression. Therefore, in the present
study we compared the cognitive performance of adults with
Appetite 52 (2009) 535–539
A R T I C L EI N F O
Received 14 March 2008
Received in revised form 30 December 2008
Accepted 6 January 2009
A B S T R A C T
There is a growing evidence that obesity is not only a weight problem, but it is linked to adverse
neurocognitive outcomes. Besides obesity, frontal lobe based cognitive deficits in depressed patients are
confirmed, and interactionsbetweendepression and obesityareknown.Inour studyweinvestigatedthe
relationship between cognitive functioning, mood and female obesity. Our findings revealed reduced
mental flexibility and sustained attention capacity in obesity together with the presence of depressive
mood. The mediating role of depression is confirmed. Positive emotion was associated with cognitive
functions independently from BMI. Positive affectivity in obesity treatment is discussed.
? 2009 Elsevier Ltd. All rights reserved.
* Corresponding author at: Institute of Physiology, Pe ´cs University Medical
School, Szigeti str. 12, P.O. Box 99, H-7602 Pe ´cs, Hungary.
E-mail address: firstname.lastname@example.org (R. Cserje ´si).
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/appet
0195-6663/$ – see front matter ? 2009 Elsevier Ltd. All rights reserved.
obesity and normal body weight controls on neuropsychological
tasks. Furthermore, the role of emotional state and their potential
impacts on executive functions has been investigated.
Participants were 30 female patients (M age = 48.8, SD ? 11; M
BMI = 34.2, SD ? 3.8) with a diagnosis of obesity seeking surgical
intervention for weight loss (Lap band surgery) in specialized clinics.
The diagnosis was done by endocrinologists and physicians before
admitting patients to the clinic. Apart from nutrition behaviour and
tendencies to over-eat, no sudden hormonal changes or metabolic
illness or any kind of genetic disease could explain the obesity. Thirty
females with normal body weight (M age = 49.3, SD ? 11; M
BMI = 22.8, SD ? 1.7) and with no diagnosis of any eating disorders
or major psychiatric disorder served as control subjects. Control
of the patients (number of years completed in school) and their social
status (current profession). There was no difference in groups for age
(t(60) = 0.06, p = 0.855), education level (t(60) = 0.03, p = 0.911),
socialstatus(t(60) = 0.14,
p = 0.825),
(t(60) = 20.94, p < 0.001) and BMI (t(60) = 22.05, p < 0.001) showed
significant differences. All participants were born in Belgium, and
their native language was French. Examinations were performed in
accordance with institutional and international (Declaration in
standards. Prior to their inclusion into the study, participants gave
their informal consent and written permission of participants was
Beck Depression Inventory II (BDI) is a 21 item self-report
inventory measuring characteristic attitudes and symptoms of
depression (Beck, Steer, Ball, & Ranieri, 1996). Each item is rated on
a 4-point scale and the total score is computed by summing each
item (range 0–63). Mild to moderate depression corresponds to
10–18, moderate to severe depression to 19–29 and severe
depression to 30–63 score ranges.
State-Trait Anxiety Inventory (STAI) is a self-rating measure of
anxiety and it consists of two parts: the STAI-STATE describing the
actual situation and the STAI-TRAIT general measure of anxiety
(Spielberger, 1983). Participants indicated their degree of approval
to 80 for each form.
Positive Affectivity and Negative Affectivity Schedule (PANAS) is a
self-rating measure of positive and negative mood state (Watson,
Clark, & Tellegen, 1988). It consists of the 10 items for Positive
Affectivity Schedule (PA) and 10 items for Negative Affectivity
Schedule (NA). Participants indicated their degree of approval on
20 items on a 5-point scale ranging from 1 (not at all) to 5
Digit span memory test (DS) is a verbal measure of immediate
memory (forward) and working memory (backward) maintenance
and manipulation (Wechsler, 1997).
The Semantic and Phonetic Verbal fluency (Benton, 1968; Milner,
1964) test is used to detect spontaneous verbal flexibility and
inhibition. The ability to generate verbal responses according to
several rules (i.e., semantic or phonemic categories) is linked to the
PFC function (Troyer, Moscovitch, Winocur, Alexander, & Stuss,
1998). The test score was the number of correct words pronounced
in one minute.
The D2 attention endurance test (D2) was chosen to measure
attention capacity, concentration ability and attention distract-
ibility (Brickenkamp, 1981).
The Trail Making Test (TMT) consists of two parts: the TMT A and
the TMT B (Reitan, 1958). Performance on test A requires a basic
level of concentration, and visuomotor tracking. Test B measures
perceptuomotor speed and inhibition. Thus, poor performance on
completion time and performance errors of the B-A may reflect
difficulties in shifting capacity (Waldstein, Snow, & Muldoon,
Hayling Sentence Completion task (Burgess & Shallice, 1997) is a
initiation and response suppression. It consists of two sets (A and
B), and it measures executive functioning through the speed
(completion time) or accuracy (number of errors) of the subjects.
The score of Hayling B assesses the ability to suppress, while
mental flexibility is operationalized by the difference between
parts A and B.
Each participant was tested individually in an examination
room by the same examiner trained in clinical neuropsychology.
Before administering the test battery, they were asked to fill up
the questionnaires. The examination lasted approximately 2 h;
participants were free to take a short break whenever they felt
tired. The MANOVAs, t-tests, correlations and linear regressions
reported herein were computed using SPSS, version 13. In order
to test our hypothesis whether the relationship between obesity
and the frontal lobe dysfunctions is mediated by mood, we used
the procedure of Baron and Kenny, well described in the study of
Friedman et al. (2002). Baron and Kenny (1986) proposed the
following criteria must be met for mediation to be possible:
The independent variable (BMI) must be significantly related to
the mediator (mood), the independent variable (BMI) must be
significantly related to the dependent variable (frontal lobe
function), the mediator (mood) must be significantly related to
the dependent variable (frontal lobe function) and the depen-
dent variable must be reduced when the mediator is included in
ANOVAs analysis revealed significantly more depression (BDI,
F(1, 58) = 22.38, p < 0.001) and state anxiety (STAI-STATE; F(1,
58) = 10.37, p = 0.002) in the obese group. In the obese group, 24
patients out of 30 reported depression (10 patients mild, 12
moderate and 2 severe depressions), while in the control group
only 10 participants scored above 10 points on the BDI (9 mild and
only one moderate). No significant group differences were found
for the general anxiety measure (STAI-TRAIT; F(1, 58) = 3.37,
p = 0.071) and for negative (NA; F(1, 58) = 0.09, p = 0.765) or
positive mood state (PA; F(1, 58) = 1.849, p = 0.180). MANOVAs
revealed that women with obesity performed significantly worse
on the D2 attention test (F(1, 58) = 4.145, p = 0.023), and on
executive function tests, such as TMT A (F(1, 58) = 5.71, p = 0.019),
Hayling A (F(1, 58) = 20.30, p < 0.001), Hayling B (F(1, 58) = 7.86,
p = 0.005) and Hayling BA (F(1, 58) = 5.31, p = 0.017). Considering
the accuracy (i.e. number of errors) of the D2, TMT and Hayling
tests, there was no difference between the two groups.
Pearson’s correlations were performed on the BMI, neuropsy-
chological tasks, depression, affectivity and anxiety (see Table 1).
The elevated BMI positively correlated with the execution time of
R. Cserje ´si et al./Appetite 52 (2009) 535–539
(D2 test). The BMI was strongly correlated with the negative
emotional status (BDI, STAI, NA). In contrary to our presumption,
the negative emotional status did not correlate with the sustained
attentions. The depression correlated positively with TMT B test.
(PA) and the performance on the D2 attention task, while PA
negatively correlated with TMT B. Positive correlation have been
found also between positive affectivity scores (PA) and the
semantic verbal fluency task (r = 0.26, p = 0.052); PA and Digit
Span backward (r = 0.42, p < 0.001). However, these results were
not included in Table 1 because of their not significant group
Based on the correlation’s results for the different factors, two
sets of regressions were carried out: 1. set of regression to test
and BA) and obesity(BMI) is mediated by depression (BDI),2. set of
regression to test whether the relationship between obesity and
sustained attention (D2) is mediated by positive emotional state
(PA). When depression (mediator) was regressed on the BMI
(dependent variable) in the first equation, the BMI was signifi-
cantly associated with depression (b = 0.644, p < 0.001). When the
dependent variables (Hayling test) were regressed on the BMI as a
second equation, the Hayling B was significantly associated with
BMI (b = 0.29, p = 0.025), while the Hayling BA was not significant
withBMI(b = 0.23,p = 0.065).Inthethirdequationdepressionwas
regressed on the Hayling test, and depression was significantly
related to Hayling B (b = 0.28, p = 0.035), while the relationship
between Hayling BA and depression was not significant (b = 0.23,
p = 0.065). When both BMI and depression were regressed on
Hayling B test, the regression for BMI was reduced when
depression was entered as a mediating variable in the regression
(b = 0.19, p = 0.245). Thus, each of the criteria outlined by Baron
and Kenny for mediation was met only for the Hayling B, which
model is presented in Fig. 1.
In the second model, positive affectivity scores (mediator) were
regressed on the BMI (dependent variable), the BMI was not
associated significantly with positive affectivity (b = ?0.134,
p = 0.301). When the dependent variables (D2 test) were regressed
on the BMI, the D2 test was significantly associated with BMI
(b = ?0.281, p = 0.027). Then, positive affectivity was regressed on
the D2 attention test, and positive affectivity was significantly
related to D2 (b = 0.453, p < 0.001). When both BMI and positive
affectivity were regressed on D2 test, instead of decreasing, the
regression for BMI was increased when positive affectivity was
entered as a mediating variable in the regression (b = 0.418,
p < 0.001). Therefore, our results did not confirm the mediation
effect of the positive affect on the relationship between BMI and
the performance on D2 attention test.
characterized by any specific deficit of executive functioning and
furthermore the relationship between different emotional state
and performance on neuropsychological tasks. When addressing
the first question about the existence of possible deficits in the
different executive functions, the overall answer is that despite
similar education level and social status, women with obesity
performed significantly worse on the D2 attention endurance test
(sustained attention) and the Hayling task (verbal mental
flexibility and inhibition capacity). These findings suggest that
problem in the sustaining attention and mental inflexibility due to
altered inhibition capacity is associated with adult obesity. These
results are in line with previous findings on both childhood (Braet
et al., 2007; Cserjesi et al., 2007) and adult obesity (Elias et al.,
2003; Gunstad et al., 2007) and they confirm the role of deficits in
executive functioning in obesity.
However, until now the role of the negative emotional status,
namely depression and anxiety, was not considered as a possible
factor influencing the cognitive performance in obesity. Clinical
observation often reveals that depressed patients frequently
complain of distractibilityand inability to handle multiple ongoing
activities. Several previous studies have confirmed the existence of
the deficits in attention and executive functions in major
depression, however, it seems that only executive functions were
associated with the severity of depression (Paelecke-Habermann,
Pohl, & Leplow, 2005; Weiland-Fiedler et al., 2004).
Therefore, secondly we investigated the relationship between
negative-positive affectivity, anxiety, depression and cognitive
performance. Our results reinforced the link between the
depression and adult obesity. Our first regression model (see
Fig. 1) confirmed the mediating role of the depression (Rogers,
Kasai,& Koji, 2004; Weiland-Fiedler et al.,2004) in the relationship
Intercorrelations for body mass index (BMI), executive functions and emotional states.
BMITMTB TMTBAHB HBA D2BDISAINA
The numbers indicate the r values of the bivariate Pearson’s correlations. TMTB = Trail Making Test part B; TMTBA = Trail Making Test part B-A; HB = Hayling part B;
HBA = Hayling B-A; D2 = attention test; BDI = Beck Depression scale; SAI = State Anxiety Inventory; NA = negative affectivity; PA = positive affectivity.
*p < 0.05.
yp < 0.01.
Fig. 1. Regression model on the relationship between frontal lobe function
(inhibition capacity) and obesity mediated by depression (BDI). The numbers
indicate b values, the effect of the predictor when the mediator is in the model. (*)
p < 0.05 and (y) p < 0.01.
R. Cserje ´si et al./Appetite 52 (2009) 535–539
between inhibition capacity(HaylingB, executive functioning)and
obesity. The mediating role of depression on the relationship
between mental flexibility (Hayling BA) and obesity was not
confirmed, however theb values show a tendency to be significant
(p = 0.065). This marginal effect can be explained in two ways:
First, our analyses had a lack of precision due to the low sample
functioning was associated with the severity of depression. In
order to assess depression, we have used BDI, which is the most
commonly referenced self-administered depression severity mea-
sure in both clinical practices and research. Probably self-
administered inventory method was not sensitive enough for
the individual differences to investigate the possible correlation
with executive functioning. Apart from the significant group
differences on the BDI scores, the obese group reported mostly
mild or moderate depression, which still could be considered as a
sub-clinical level of depression. Therefore, another possibility is
that mean depression level amongst our obese participants was
not high enough to have an impact on the frontal lobe based
mental flexibility. This idea is reinforced by the fact that despite
significantly higher depression, no general psychomotor or verbal
retardation was found in the obese group. Neuropsychological
studies of executive function in clinical depression have identified
deficits in working memory, cognitive set-shifting and planning
tasks (Rogers et al., 2004). In fact, diminished ability to
concentrate, indecisiveness and psychomotor retardation (e.g.,
slowed speech and thinking) are included among the key
diagnostic criteria for clinical depression (DSM-IV, 2000).
Reduced sustained attentional capacity did not correlate with
depression in obesity. We have found that positive affectivity was
correlated with most of the neuropsychological tasks together
with the D2 attention task (e.g. D2 attention test, verbal fluency,
digit span backward and TMT) in both obese and control groups.
Williams et al. (2002) have found that dieting was associated
with deficits in sustained attention. As our patient group was
under medically imposed diets, dieting can be an appropriate
answer for the attentional problem on D2 test. Eating is a highly
motivated and reinforced behaviour, the reward/non-punishment
or punishment/omission of rewards is used to regulate this
behaviour (Gray, 1987). Davis, Levitan, Muglia, Bewell, and
Kennedy (2004) showed higher sensitivity to immediate rewards
in overweight and obese adult women. Obese individuals’
difficulties in inhibiting or modifying current behaviours, sus-
tained attention and less appropriate cognitive control, can be
related to the lack of positive emotional state (reward). Cognitive
studies reported that induced positive mood facilitates informa-
tion processing, when creativity and mental flexibility were
required (Gasper & Clore, 2002; Isen, 1987). Mental flexibility,
creative thinkingand the ability to ‘‘think outside the box’’ are very
important capacities in the everyday life, they are necessary to be
able to change unhealthy life style or to resolve personal problems
by looking for different alternatives.
Kaplan (2001) proposed that when people are required to focus
their attention and put forth sustained cognitive effort (e.g.
dieting), it may lead to mental fatigue. In turn, this may result in
irritability, anxiety, anger, frustration, mental and physical fatigue,
and may further diminish the ability to successfully perform
cognitive tasks and address social demands (Kuo & Sullivan, 2001).
Mental restoration is commonly considered a reversal of these
effects, allowing for increased critical thinking, concentration and
sustained focus (Kaplan, 2001).
One limitation of our study should be discussed. Consistent
with the past literature, we interpreted and presented obesity in
this study as a consequence of pathologically elevated BMI.
However, recent studies reported two different types of obese
people. Pinaquy, Chabrol, Simon, Louvet, and Barbe (2003)
indicated that obese women who have difficulty identifying and
communicating their feelings have a tendency to eat in response to
emotions, specifically negative emotions. Williams et al. (2002)
suggested that different aspects of eating behaviours have
dissociable effects on cognitive-affective function. In the future
into account when the role of affective states on neurocognitive
functions will be investigated.
In summary, this study supports the idea that the deficit in
executive functions – specifically, sustained attention, lack of
control, and depression – are linked to the state of obesity.
Importantly, our results showed that positive affectivity facilitates
the cognitive capacities. Therefore, the treatment of depression,
and the facilitating effect of positive emotions in the improvement
of cognitive control should be integrated in the clinical practices.
In this manner, healthcare providers can work to treat both
conditions (affective problems and obesity) together, rather than
obesity in isolation.
This study was supported by ETT 317/2006, RET-008/2005
MEDIPOLIS, NKTH-OTKA K68431 and by the HAS. We would like to
thank to the physicians for their help in recruitments. We would
like to thank also to the participants for their time and availability.
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