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Health complaints in children with attention-deficit/hyperactivitydisorder
KIRSTEN HOLMBERG1 & ANDERS HJERN2,3
1Department of Woman and Child Health, Neuropaediatric Unit, Karolinska Institute, Astrid Lindgren Children Hospital,
Karolinska University Hospital, Stockholm, Sweden, 2Department of Women’s and Children’s Health, Section for Paediatrics,
Uppsala University, Uppsala, Sweden, and 3Centre for Epidemiology, National Board of Health and Welfare, Stockholm,
Sweden
AbstractAim: To assess recurrent subjective health complaints in Swedish schoolchildren with attention-deficit/hyperactivitydisorder (ADHD). Methods: Cohort study of 577 fourth-graders (10-y-olds) in one municipality in Stockholm County. Allchildren were screened for attention and behaviour problems through interviews with their parents and teachers. Childrenwith high scores underwent further clinical and cognitive assessments. Information about health complaints was collectedfrom the children themselves in a classroom questionnaire. The 516 children for whom there was information from all threedata sources were included in the final study population. Hypotheses were tested in multivariate analyses with adjustmentfor sex and parental education. Results: Recurrent abdominal pain (RAP), sleeping problems and tiredness were associatedwith ADHD (stratified relative risks: 2.2 [1.4�3.4], 1.7 [1.1�2.7] and 2.7 [1.7�4.1], respectively), while there was noassociation with headache.
Conclusion: This study indicates that treatment strategies for children with ADHD need to include an effective evaluationand treatment of RAP, tiredness and sleeping disturbances. Evaluation of ADHD should be considered in children withrecurrent health complaints.
Key Words: ADHD, health complaints, psychosomatic, schoolchildren
Introduction
Attention-deficit/hyperactivity disorder (ADHD) [1]
is one of the most common child psychiatric distur-
bances, affecting 3�5% of school-aged children in
Swedish population-based studies, and 7�10% if
children with less severe symptoms are included [2�4]. The core symptoms of ADHD (inattention,
hyperactivity and impulsivity) [1] are often associated
with troublesome interpersonal relationships with
family members and peers as well as difficulties in
the classroom [5,6]. Cognitive impairments overlap to
a certain extent with ADHD and may further
complicate the situation in school [7]. Children
from households with a disadvantaged socio-eco-
nomic situation are more often diagnosed with
ADHD [8].
Subjective health complaints refer to symptoms
experienced by the child with or without a defined
diagnosis [9]. Common childhood health complaints
include pain syndromes such as headaches, recurrent
abdominal pain (RAP) and back pain [9�11] as well
as symptoms of a more psychological nature*irrit-
ability, nervousness, sleeping difficulties and daytime
tiredness [9,12]. Recurrent pain appears to have
negative effects on the development of children with
associated school problems and is frequently the cause
of absence from school [9].
Recent analyses of a nationally representative
sample of Swedish children in the ages 10�18 y
have demonstrated that troubled relations with
peers and parents and economic stress in the family
are risk factors for health complaints [13]. Con-
sidering this, it seems reasonable to hypothesize
that subjective health complaints might be more
common in children diagnosed with ADHD. We
decided to test this hypothesis in a population-
based sample of Swedish fourth-graders in a suburb
of Stockholm, and include factors for intellectual
impairment and indicators of socio-economic dis-
advantage.
(Received 28 November 2005; accepted 24 March 2006)
ISSN 0803-5253 print/ISSN 1651-2227 online # 2006 Taylor & Francis
DOI: 10.1080/08035250600717121
Correspondence: Kirsten Holmberg, Neuropaediatric Unit, Karolinska Institute, Astrid Lindgren Children’s Hospital, Q2:07, Karolinska University Hospital,
SE-171 76 Stockholm, Sweden. Tel: �/46 8 517 77341. E-mail: [email protected]
Acta Pædiatrica, 2006; 95: 664�670
Subjects and methods
The entire study population comprised all 577
children (282 girls, 295 boys) in the fourth grade
(20 born in 1990, 539 born in 1991, 18 born in 1992)
during the academic year 2001�2002 in Sigtuna, a
municipality in Stockholm County. All schools (main-
stream as well as special) in the municipality partici-
pated in data collection. Ethical approval for the study
was granted by the ethics committee at Karolinska
Institute, Stockholm.
Child interviews
Information about health complaints was collected
from the children themselves in a classroom study.
The questionnaire included four items from the
questionnaire used in the WHO study ‘‘Health
Behaviour of School-aged Children: headache, ab-
dominal pain, difficulties in falling asleep and day
tiredness’’ [9,12]. The frequency of pain symptoms
was classified on four levels (never, once a month,
once a week, daily), as suggested by Hagquist [14].
The questionnaire was administered by the school
nurse. Children who were absent from school at the
time of the classroom study were approached by the
school nurse within the next few weeks and given a
second opportunity to fill in the questionnaire. In the
end, questionnaires from 97% of the children were
returned.
Parent interviews
Parents were asked to complete a questionnaire in
connection with a routine health examination of their
fourth-grade children. This questionnaire included
Conners’ 10-item scale [15], the executive functions
screening scale (EFSS), and some questions about the
socio-demographic characteristics of the household.
The EFSS was designed especially for this study to
identify children with attention problems who are not
hyperactive or impulsive. It consisted of 17 items
pertaining to passive and slow behaviour and learning
difficulties, and has been presented in detail elsewhere
[16]. The socio-demographic questions included
sex of the child, maternal country of birth and
maternal educational level. Educational level was
recorded in three categories: 9 y or less of basic
education, more than 9 y of basic education but less
than 3 y of university education, and 3 or more
years of university education. Maternal country of
birth was recorded as Sweden, other Nordic coun-
tries, other European countries, and the rest of the
world. Parent questionnaires for 91.9% of the chil-
dren were returned.
Teacher interviews
The Conners’ scale and the EFSS were distributed to
the children’s teachers together with the ADHD
symptom scale according to the Diagnostic and
Statistical Manual of Mental Disorders, fourth edition
(DSM-IV) [1]. Each teacher was also interviewed by
the first author (KH) regarding learning and beha-
viour problems. Information from the teachers was
received for all children in the study.
Clinical assessment
A score of at least 10 (possible range of scores 0�30)
on the Conners’ scale was used as the cut-off point
that indicated behavioural problems, as suggested by
earlier studies [3]. In this cohort, 10.2% scored above
the cut-off point in the parent reports and 13.4% in
the teacher reports. In the EFSS, a score of at least 17
(possible range of scores 0�51) indicated behavioural
problems, learning problems, or both [16]. At this
cut-off, 10.5% and 16.8% of the children had such
problems according to the assessments of the parents
and teachers, respectively. Children were considered
for inclusion in the clinical part of the study according
to the following criteria: 1) ratings above the cut-off
points on at least two questionnaires, and 2) a rating
above the cut-off point on at least one questionnaire in
combination with significant problems reported by
the teacher, such as a known developmental disorder
or if the child had had to repeat a grade.
On the basis of these inclusion criteria, 160 children
were screened positive. Of these, 145 (91%) agreed to
participate in a clinical assessment by the first author
(KH), which included a structured diagnostic inter-
view with the parents focusing on general paediatric
and developmental issues, as detailed in a previous
paper [16]. The ADHD symptom scale according to
DSM-IV was completed by the parents at the end of
the interview. The parents were offered a psychologi-
cal examination for their child, including a cognitive
assessment according to WISC-III [17]. Psychological
examinations were performed on 124 children. All
parents were later invited back to receive feedback on
their child’s test results and to discuss possible further
interventions.
Clinical outcomes
ADHD symptoms were categorized by KH into four
different categories based on information from the
parents, the teachers and the clinical assessment. The
four categories, ‘‘pervasive ADHD’’, ‘‘situational
ADHD’’, ‘‘subthreshold ADHD’’, and ‘‘no ADHD’’,
were classified at the time of the clinical assessment
according to the following criteria: i) ‘‘pervasive
ADHD’’*children who met criteria for ADHD
Health complaints in children with ADHD 665
according to DSM-IV (six or more inattentive symp-
toms, six or more hyperactive-impulsive symptoms, or
both) at home according to the parent or at school
according to the teacher, with some impairment from
the symptoms in both settings; ii) ‘‘situational AD-
HD’’*children who fulfilled the criteria for ADHD
either at home according to the parent but not the
teacher (home-only ADHD) or at school according to
the teacher but not the parents (school-only ADHD)
and with no reported impairment from the symptoms
in the other setting [18]; iii) ‘‘subthreshold AD-
HD’’*children with four or five inattentive symp-
toms, four or five hyperactive-impulsive symptoms, or
both at home, in school, or both at home and in
school [19]; iv) ‘‘no ADHD’’*all other children,
including those who were not selected for clinical
assessment. Impairment was assessed through parent
and teacher interviews. Information about ADHD-
related symptoms present before the age of 7 y was
collected from records at Child Health Centres and
parent interviews.
Attention and hyperactivity symptoms in the 15
screen-positive children who did not participate in the
clinical examination were assessed by information
from parent and teacher questionnaires, teacher inter-
views, school nurses, and some telephone interviews
of parents. None of the drop-outs were judged to have
severe behavioural or attention problems, and were
therefore included in the study population in the ‘‘no
ADHD’’ group.
Statistical analysis
Dichotomized outcome variables of health complaints
were created by defining symptoms present at least
once a week as ‘‘yes’’ and all other symptoms as ‘‘no’’.
Daytime tiredness was defined as ‘‘yes’’ only if present
every day. Associations of these variables with the
categories ‘‘pervasive ADHD’’ and ‘‘situational
ADHD’’ collapsed into a single group were tested in
a stratified analysis adjusted for gender and parental
educational level using the Mantel-Haenzel procedure
[20]. Chi-squared analyses were used in vicariate
analyses. Statistical analyses were carried out using
the SAS 8.0 software package for Windows.
Results
Children for whom there was information from all
three data sources*the child, the parent and the
teacher*were included in the final study population.
They comprised 89.4% (516/577) of all children in
grade four in Sigtuna.
Of the 516 children surveyed, 264 were boys (51%)
and 252 were girls (49%). Twenty-one children were
being educated in small groups because of special
education needs. Four of these children attended a
special school for children with mild mental retarda-
tion. Nineteen per cent of the children had mothers
with a university degree, while another 56% had
at least some secondary education. Fourteen per
cent of the children had mothers who were born
outside Europe, while 23% had a foreign-born mother
(Table I).
The overall prevalence of complete (pervasive)
ADHD syndrome was 5.6% (29/516); 75.9% (22/
29) had the combined type, 20.7% (6/29) were of the
inattentive type, and 3.4% (1/29) were hyperactive-
impulsive according to DSM-IV [1]. Both ‘‘pervasive’’
and ‘‘situational ADHD’’ were more common in boys
than girls (boys 18.2%, girls 5.2%; pB/ 0.001) and in
children from households where the parents had little
education (ADHD 18.8%) compared to households
where parents had a university education (8.1%) (pB/
0.05). There were no major differences in the
prevalence of ADHD in children from foreign-born
Table I. Socio-demographic variables in children with attention-deficit/hyperactivity disorder (ADHD).
Socio-demographic
variables n %
No ADHD
(n�/420) %
Subthreshold ADHD
(n�/35)
%
Situational ADHD
(n�/32)
%
Pervasive ADHD
(n�/29)
%
Sex
Boys 264 51 74 8 9 9
Girls 252 49 89 6 3 2
Maternal education
0�9 y 128 25 75 6 13 6
11�12 y 289 56 82 8 3 7
13�/ y 99 19 87 5 6 2
Country of birth of mother
Sweden 398 77 82 7 6 5
Other Nordic countries 27 5 89 4 0 7
Other European countries 18 4 72 5 17 6
Rest of world 73 14 78 8 6 8
666 K. Holmberg & A. Hjern
and Swedish-born parents (Table I). The cate-
gory ‘‘situational ADHD’’ comprised children whose
assessments by the parents and the teacher differed
strongly. In this group, 78% (25/32) fulfilled the
DSM-IV criteria in school (school-only ADHD) and
had only a few symptoms at home, while 22% (7/32)
had ADHD symptoms according to the parent and no
impairment in school (home-only ADHD).
Sixty per cent of the children in the study reported
at least one health complaint and 33% at least two
complaints. Difficulties falling asleep were reported
weekly for 40%, headache for 27% and RAP for 23%,
while daytime tiredness occurring each day was
reported for 20%. Girls tended to have slightly higher
prevalences for recurrent headache, RAP and sleeping
disturbances (Table II). Health complaints once a
week tended to be reported less commonly in children
from households where the parents had a university
degree and in children in households where the
parents were born outside Sweden (Table II). The
21 children educated in small groups tended to report
fewer health complaints per week compared with the
other children. Only 14% of the children in small
classes reported two or more health complaints, while
57% reported at least one. The corresponding pre-
valence for children in normal classes was 34% and
60%.
Eighty per cent of the boys in the categories
‘‘pervasive’’ and ‘‘situational ADHD’’ reported at
least one health complaint, while 56% had at least
two complaints, compared with 50% and 25%,
respectively, in boys with ‘‘no ADHD’’. The pattern
was similar in the girls, with the difference that
girls with ‘‘subthreshold ADHD’’ tended to report
higher frequencies of health symptoms compared to
girls with ‘‘no ADHD’’, while boys in the ‘‘subthres-
hold’’ group had rates similar to those of the boys in
the category ‘‘no ADHD’’ (Table III). The crude
relative risk (RR) for RAP in the categories ‘‘perva-
sive’’ and ‘‘situational ADHD’’ compared to the rest
of the population was 2.3, for sleeping problems
1.8, and for tiredness 2.9, while the RR for head-
ache was 1.1.When the analysis was stratified for
maternal education and sex of the child, the RR
decreased slightly to 2.1, 1.7, 2.7 and 1.0, respectively
(Table IV).
Children with ADHD and low cognitive tests scores
(IQB/85) tended to report at least one health com-
plaint slightly less often (70%) than children with
ADHD and a test score in the normal range (IQ]/85)
(84%). In the group with normal test scores, children
with ADHD had higher prevalences of health com-
plaints compared to children without ADHD (pB/
0.001). This was not seen in the group with low test
scores.
Discussion
This population-based study demonstrates that chil-
dren with ADHD report RAP, sleeping problems and
daytime tiredness about twice as often as other
children. The risk increase was similar in children
who fulfilled the ADHD criteria in one or two settings
(home and school).
The symptoms of ADHD often affect relations with
peers, parents and teachers in a negative way [5,6].
Recent studies have demonstrated that poor peer,
teacher and parental relations are associated with
health complaints [12,13,21]. Further investigations
are needed to clarify the role of troubled relations in
the development of health complaints in children
diagnosed with ADHD. Particular attention should
be paid to bullying, which has been demonstrated to
be a particularly important risk factor for health
complaints [12,13,21].
Table II. Socio-demographic variables in children with health complaints.
Socio-demographic
variables n
Headache
%
Recurrent
abdominal
pain
%
Sleeping
problems
%
Daytime
tiredness
%
At least one
complaint
%
At least two
complaints
%
Sex
Boys 264 24 21 36 21 55 30
Girls 252 29 26 43 19 65 35
Maternal education
0�9 y 128 30 26 41 14 63 31
10�12 y 289 26 25 40 24 60 36
13�/ y 99 25 15 37 18 57 26
Country of birth of mother
Sweden 398 29 23 42 21 62 35
Other Nordic countries 27 26 22 44 11 52 30
Other European countries 18 6 28 39 33 61 33
Rest of world 73 19 23 29 19 51 23
Health complaints in children with ADHD 667
It is also possible that there is a common neurobio-
logical pathway underlying the association between
ADHD and health complaints. Deficits in working
memory and self-regulation that are common in
children with ADHD may impair their ability to
interpret and process stressful stimuli [22]. Hypothe-
tically, the association of ADHD with health com-
plaints could be mediated through disturbances in the
hypothalamic-pituitary-adrenal (HPA) axis as well as
the sympathetic-adrenal-medullary (SAM) system
[23]. Neurophysiological connections between stress
and ADHD are an important area for future explora-
tion in ADHD research.
ADHD and, to a certain extent, health complaints
are associated with socio-economic disadvantage. In
the stratified analysis, however, the relative risk of
ADHD for health complaints decreased only margin-
ally when parental education was adjusted for, sug-
gesting that the socio-economic situation of children
with ADHD does not explain the association of
ADHD to health complaints.
Several earlier studies have demonstrated a ten-
dency for headache and RAP to vary in a similar
manner in relation to important risk factors [10,21].
This study, however, demonstrates an association
between ADHD and RAP but not with headache,
thereby duplicating results from a study by Egger
et al. [24]. This could be an artefact related to our
comparatively small study populations of children
with ADHD, but is otherwise an intriguing finding,
suggesting a specific mechanism for ADHD as a risk
factor for RAP.
Children with significant impaired behaviour in one
or two settings reported increased prevalences of
health complaints. Most of the children had ‘‘perva-
sive ADHD’’ of the combined type (inattention,
hyperactivity and impulsivity), and teachers also
reported high frequencies of inattentive, hyperactive
and impulsive behaviour in children in the ‘‘school-
only ADHD’’ group. This observation suggests that
behaviour problems in school may result in relation
problems with peers and teachers and secondary
psychosomatic symptoms, or the other way around,
even if the home situation is balanced.
While girls with ADHD problems in the ‘‘subthres-
hold’’ group reported health complaints more fre-
quently than girls with ‘‘no ADHD’’, this was not
observed in the boys. This might be some support for
claims that ADHD symptoms in girls are not recog-
nized as easily as in boys, since girls are less
hyperactive [25]. An alternative explanation could
be that less severe behavioural disturbances affect the
social relations of girls more than of boys, as has been
suggested by Blackman and Hinshaw [26].
Sleep disturbances have been found in preschool-
aged children with hyperactivity and in young school-
children with ADHD [27]. This study shows that
sleeping problems seem to persist in older children
with ADHD.
The findings in this study of a higher risk of health
complaints in children with attention problems con-
trasts with the findings of an earlier Swedish study by
Rasmussen and Gillberg [28], where such risks were
absent. They studied younger children (6�11 y),
where the prevalence of health complaints generally
tends to be lower [13] and bullying is somewhat less
common [12]. The study by Rasmussen and Gillberg
Table III. Crude rates of health complaints at least once a week in children with attention-deficit/hyperactivity disorder (ADHD).
Headache
Recurrent
abdominal
pain
Sleeping
problems
Daytime
tiredness
At least one
complaint
At least two
complaints
ADHD
category
Total
n
Boys
n
Girls
n
Boys
%
Girls
%
Boys
%
Girls
%
Boys
%
Girls
%
Boys
%
Girls
%
Boys
%
Girls
%
Boys
%
Girls
%
No ADHD 420 196 224 22 29 14 25 33 42 17 16 50 63 25 33
Subthreshold
ADHD
35 20 15 30 40 20 47 30 47 10 60 50 80 25 67
Situational
ADHD
32 23 9 30 22 52 11 48 56 44 56 78 78 57 56
Pervasive ADHD 29 25 4 28 25 44 25 60 50 44 0 80 75 56 25
Total 516 264 252 24 29 21 26 36 43 21 19 55 65 30 35
Table IV. Stratified analyses of health complaints and attention-
deficit/hyperactivity disorder (ADHD) (pervasive or situational
(ADHD).
Model 1 RR
(95% CI)
Model 2 RR
(95% CI)
Recurrent abdominal pain 2.3 (1.4�3.7) 2.2 (1.4�3.4)
Headache 1.1 (0.6�1.8) 1.0 (0.6�1.6)
Sleeping problems 1.8 (1.2�2.9) 1.7 (1.1�2.7)
Day tiredness 2.9 (1.8�4.6) 2.7 (1.7�4.1)
Model 1 is crude. Model 2 is adjusted for sex and maternal edu-
cation.
RR: relative risk; CI: confidence interval.
668 K. Holmberg & A. Hjern
[28] was carried out in the 1970s; thus, it is possible
that the differing results reflect the change in teaching
methods in Swedish schools that has taken the last
three decades, where recent methods tend to make
greater demands on children to plan and organize
their school work. It is also possible that the use of
children themselves as informants in the present study
made it easier to detect this association, since children
themselves are probably the best source of informa-
tion on health complaints [29].
Limitations
The major limitation of this study is that the data were
collected within the school health system and used in
connection with health visits to the school nurses and
physicians. This means that the information may have
been biased by thoughts about how it would be used
within the school. It seems possible, for example, that
parents and children may have withheld information
about health and behavioural problems if they pre-
ferred to find solutions to these problems outside of
school. To a certain extent, this problem was mini-
mized in the area of behaviour and school problems
by using teachers as informants, but for health
complaints, the only data available were the informa-
tion collected from the children. The rates of ADHD
and health complaints in this study, however, are quite
similar to reports in other recent Swedish studies
[3,4,13], which seems to indicate that this bias was
minor.
This method of data collection, however, is also the
greatest strength of this study, since it explains the
extraordinarily high participation rate of parents,
teachers and children. The fairly low participation
rate (124/160, 77.5%) in the WISC testing for
children selected in the screening makes it necessary
to interpret the findings regarding children with
intellectual disabilities with certain caution, but other-
wise, the results presented can be expected to be
representative of the entire study population. Another
strength of the study is the use of multiple informants
where data on behaviour are provided by both
teachers and parents, data on socio-economic condi-
tions by parents, and data on health complaints by the
children themselves [29]. This structure also made it
possible to evaluate the behaviour of the drop-outs,
whose Conners’ scores rated by teachers were similar
to those of the study population (mean 4.7 vs 4.3,
respectively), as were the EFSS scores rated by
teachers (mean 9.3 vs 8.4, respectively), thus suggest-
ing that the study population was fairly representative
of the whole cohort.
The comparatively low age of the children in the
classroom study makes the children’s reading and
writing skills of Swedish a possible source of bias. It is
possible that difficulties of this kind affected responses
of children with cognitive difficulties, foreign-born
parents, or both. Thus, the results regarding these
children should be interpreted cautiously.
Can the results of this study be generalized for all
children with ADHD? Sigtuna is a medium-sized
municipality with a population that reflects fairly well
the socio-economic situation of the country on a
whole in terms of education and immigrants. The
school system is similar to the systems in most
Swedish communities, with a preponderance of com-
munity-run schools with mainstream teaching meth-
ods. Thus, it seems quite probable that the results are
representative of most societal contexts in Sweden. A
major limitation of this study, however, is the limited
age variation in the study population. School demands
and peer-relation patterns as well as the prevalence of
ADHD and health complaints vary considerably with
age, which suggests that the results of this study may,
to a certain extent, be specific for the age group
studied.
Clinical implications
Difficulties in school often constitute the main pro-
blems of children diagnosed with ADHD. Health
complaints such as recurrent headache, RAP and
sleeping disturbances can be expected to aggravate
these problems in school by interfering with learning
and causing school absence. Thus, it is important that
treatment strategies for children with ADHD also
include an effective evaluation and treatment of these
conditions.
The prevailing definitions and distinctions between
physical and psychological pain limit our understand-
ing of children’s experiences, and adversely shape the
way that paediatricians and psychiatrists treat chil-
dren’s somatic complaints. For example, a child who
reports recurrent stomach aches to a primary-care
physician may receive an extensive medical work-up
before being evaluated for a psychiatric disorder. Our
findings suggest that children who present with
recurrent health complaints should be assessed for
ADHD symptoms. Other studies have found health
complaints to be associated with childhood depres-
sion and conduct disorder [24,30]. As our under-
standing of the biological substrates and mechanisms
of psychiatric illnesses grows, so will our knowledge of
the role of psychopathology in both the aetiology and
presentation of a variety of somatic symptoms [24].
In this article, we have demonstrated that, irrespec-
tive of socio-economic confounding, children diag-
nosed with ADHD have health complaints such
as RAP, sleeping problems and daytime tiredness
more often than other children. Further studies are
needed to clarify the mechanisms responsible for this
association.
Health complaints in children with ADHD 669
Acknowledgements
Financial support for this study has been provided by
grants to the first author from the Swedish Society of
Medicine, the First of May Flower Annual Campaign,
and Samariten Foundation. We thank the school
authorities of Sigtuna, the school nurses and the
teachers, without whose assistance the study could
not have been completed. We also thank Hans
Forssberg and Elisabeth Fernell for support in initiat-
ing this study, and Ulla Ek for administering the
WISC-III test to 145 children.
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670 K. Holmberg & A. Hjern
