Introduction
Attention deficit hyperactivity disorder (ADHD) is characterized by problems, such as difficulty in paying attention, excessive activity, or difficulty controlling behavior, which is not appropriate for their age and situation. A great body of literature confirms that individuals with ADHD face psychiatric or neurologic comorbidities. Eating disorders and abnormal eating behaviors are among the common co-morbidities that are studied in ADHD in the last decade [1, 2]. Data reveal that individuals with clinical ADHD are more likely to experience a clinical eating disorder, binging/purging behaviors, and restrictive behaviors [3]. ADHD is 3.8 times more likely to present with any eating disorder as a comorbid diagnosis, and the risk increases to 5.7 times for bulimia nervosa [4, 5]. People with ADHD have a higher risk of comorbidity with an eating disorder and people with an eating disorder have higher levels of comorbidity with ADHD [5]. However, most research on children’s eating issues has focused on related eating problems, not eating disorders (namely anorexia nervosa, bulimia nervosa, and binge eating). For instance, some studies have shown that children with ADHD are in more danger of bulimic behaviors, binge eating, or limiting food intake [6, 7]. It has been shown that ADHD during childhood would predict bulimia in adolescence [8]. The presence of an eating disorder in girls with ADHD heightens the risk of additional morbidity and dysfunction. On the other hand, it has been mentioned that a higher prevalence of obesity among children with ADHD can be associated with more serious difficulty in reducing body weight, dietary compliance, and control of eating [6]. A study attempted to establish functional linkages between childhood exposure to television, ADHD, and obesity. It concluded that obesity and ADHD demonstrate significant comorbidity [2]. Some explanations have been proposed regarding the association between ADHD and eating problems, including core symptoms of inattention and impulsivity, as well as dopamine dysregulation, depression, interpersonal problems, executive dysfunction, and genetic factors [2, 4].
ADHD symptoms and impulsivity predicted both emotional and binge eating in adult women. These variables were positively associated with body mass index (BMI). People with emotional eating consume food in response to negative emotional conditions, such as anxiety, depression, and loneliness [3, 8]. Moreover, dissatisfaction with body image is common in adolescent girls with ADHD, which may be associated with frequent bouts of binge eating and bulimia. The probability of loss-of-control eating behavior increased when the scores on two different impulsivity tests were higher, regardless of adolescents’ ADHD status [11]. Such eating behavior may stimulate the dopamine reward system in the brain [2], a finding in line with higher rates of substance abuse in obese women with concurrent ADHD and eating disorders [2]. Difficulty with executive function in people with ADHD may make self-regulation difficult. This is a problem leading to overeating for the satisfaction of the need for brain stimulation. This is a hinder to eating healthily [2, 4]. Common genes in people with ADHD, binge eating disorder, and obesity have been identified which are involved in transmitting dopamine in the brain [4, 6-8]. A Review of existing literature on the comorbidity of eating problems and ADHD shows that most findings are related to adults. However, ADHD is a developmental disorder with long-term negative consequences, such as being overweight, obesity, and diabetes which usually begins in childhood and continues to adulthood. Besides, there are controversies on the association between ADHD diagnosis, weight, and eating behaviors among children. Accordingly, this study aims to compare eating problems in a group of school-aged ADHD children and their parental feeding practice compared to typically developing (TD) children. The association of eating behaviors and feeding styles with weight, BMI, and the severity of ADHD symptoms were evaluated as well. Determining common eating problems in children with ADHD and their probable mediating factors can help in both secondary or targeted prevention of eating disorders and tertiary prevention via patient-specific treatment plans.

Materials and Methods 
This descriptive-comparative study was conducted from March to December 2017 and included children in the age range of 6 to 11 years old. Children with a new diagnosis of ADHD were selected from referrals to the child and adolescent psychiatric clinic at Roozbeh Hospital, a tertiary academic center. They were diagnosed by a board-certified child and adolescent psychiatrist based on The diagnostic and statistical manual of mental disorders, fifth edition (DSM5) criteria. The kiddie schedule for affective disorders and schizophrenia (K-SADS-PL) for DSM-5 was performed to confirm the diagnosis and evaluate the comorbidities. The revised Conner parent rating scale (CPRS-R) was completed by parents to measure the severity of ADHD symptoms. The participants were excluded if they had any history of pregnancy and perinatal complications or any major comorbid psychiatric, neurologic, and medical disorders, IQ scores lower than 70 based on the Raven IQ test, taking any medication including stimulants, atomoxetine, bupropion, fluoxetine, risperidone, anticonvulsants, and corticosteroids during or/and two weeks before the study. Among the 120 children who were diagnosed with ADHD, 2 participants with obsessive-compulsive disorder, 1 with a tic disorder, 1 with enuresis, 7 with anxiety disorders, and 14 because of weak therapeutic compliance were ruled out. Finally, 95 children with ADHD were enrolled. The TD children were chosen from the students studying at mainstream elementary schools in different regions of Tehran, Iran. TD children had no histories of psychiatric problems based on their parents’ reports. The parents were informed about the goals and method of the study and offered their informed consent. A demographic questionnaire was completed by the parents regarding general information. The strength and difficulties questionnaire (SDQ) and the CPRS-R were completed by the parents for screening children’s psychopathology. If the scores were lower than the cut-off points, the children were enrolled in the study. From the 200 distributed questionnaires, 130 questionnaires were returned. Among them, 110 students passed the inclusion criteria and participated in the study. For all the participants in the two groups, BMI was calculated using a weighing machine (digital scale Zyklausmed ZYKDS06 model, tape-measure, and the following formula: BMI=weight (kg)/size (m2). The child eating behavior questionnaire (CEBQ) and the comprehensive feeding practice questionnaire were completed and accomplished by the parents.
Sample size
Based on previous studies [9], the sample size was calculated at 58 persons for each group. Considering the probable drop of some participants, the sample size was determined to be 90 children in each group.
Study measures
The study instruments were as follows:
Raven progressive matrices
The Raven progressive matrices [10] is a non-verbal test used to measure the general intelligence of participants. 
The kiddie schedule for affective disorders and Schizophrenia-Persian version
The K-SADS-PL Persian version is a semi-structured interview to diagnose childhood psychiatric disorders in school-aged children in terms of past and recent psychopathological episodes. Using the Persian translation showed that the reliabilities of ADHD, oppositional defiant disorder, and tic disorder were 0.81, 0.67, and 0.56; respectively. The inter-rater reliabilities for ADHD and oppositional defiant disorder were in a sequence of 0.69 and 0.69, respectively. Tic disorder, posttraumatic stress disorder, panic disorder, and ADHD had the highest positive predictive validities [11, 12].
The revised conner parent rating scale
There are two versions of the CRS-R. One version is completed by a parent (CPRS-R) while the other is filled out by a teacher (CTRS-R). The parent’s version has 27 questions and is designed for children in the age range of 3 to 17 years. Most of the questions are loosely based on behavioral characteristics that are described in the DSM-IV diagnostic guidelines for ADHD. Each question asks for a score from 0 to 3 (where 0=not true at all or never, 1=just a little true/occasionally, 2=pretty much true/often, and 3=very much true/very often). The questions can be divided into 4 different groups. This allows for 4 separate subtotals to be calculated, as well as a total score (which is the sum of the subgroups). The different subtotals are as follows: A (oppositional), B (cognitive problem/inattention), C (hyperactivity), and D (ADHD) index. For screening ADHD, subtotals C and D, and the overall total score are seen as the most useful. Therefore, the minimum total score according to both scales could be ‘0’ and the maximum could be ‘81’ for the CPRS-R [13]. Tehrani Doost et al. found that CPRS-R has good internal reliability coefficients, high test-retest reliability, and effective discriminative power in an Iranian clinical population [14].
Comprehensive feeding practice questionnaire
The comprehensive feeding practice questionnaire (CFPQ) is a good tool for measuring the feeding practices of young children’s parents. This tool is made up of the following scales: monitoring, emotion regulation, environment, food with a different type of reward, cooperation, patterning, coercion, education about nutrition, limitations for health, limitations for weight control, encouragement for balance, and variety. This research uses a 49-question form of CFPQ. The first 13 questions had a 5-point response scale (never, rarely, sometimes, mostly, and always). The remaining questions had a 5-point scale (disagree, slightly disagree, neutral, slightly agree, and agree). Questions number 16, 37, and 42 were reversely coded [15]. The intra-class correlation coefficient (ICC) was in the range of 0.80 to 0.91 and the Cronbach α was obtained in the range of 0.80 to 0.90 [16].
Children eating behavior questionnaire
The CEBQ is designed to assess children’s eating styles. This parent-report measure includes 35 items, each rated on a 5-point Likert scale, i.e. 1=never, 2=rarely, 3=sometimes, 4=often, and 5=always. CEBQ includes 8 subscales: food responsiveness, emotional over-eating, enjoyment of food, desire to drink, satiety responsiveness, slowness in eating, emotional under-eating, and food fussiness [17]. In an Iranian study, the internal reliability was obtained at 0.72 to 0.91, and the test-retest reliability was calculated in the range from 0.52 to 0.87 [18]. 
Strength and difficulties questionnaire
SDQ is a brief behavioral screening questionnaire for children in the age range of 3 to 16 years. This tool includes 5 subscales: emotional symptoms, conduct problems, hyperactivity/inattention, peer relationships, and prosaically behavior [19]. Each subscale of the SDQ (conduct problems, hyperactivity-inattention, emotional symptoms, peer problems) contains 5 items that are rated on a 3-point Likert scale (0=not true, 1=somewhat true, and 2=certainly true). Each subscale is calculated by adding the scores on the relevant items (after reversing indicated items). A total score can be calculated by adding the scores of the 4 difficulties subscales, with higher scores reflecting greater difficulties. Higher scores on the prosocial behavior subscale reflect more strength [20]. The sensitivity of the Persian version has been estimated as 95% for the total score. The internal consistencies of the parent SDQ and teacher SDQ total scores were 0.73 and 0.69, respectively [21].
Statistical analysis
The statistical analysis was performed via the SPSS software, version 19. The Chi-square test was used to compare the qualitative variables and the t-test was employed to compare the quantitative variables. The rejection of the Null hypothesis was set at P<0.05. The normal distribution of the data was assessed using the Kolmogorov–Smirnov test and the Pearson correlation coefficient was applied to assess the correlation.

Results
Sample identification
According to Table 1, no significant differences were observed in the demographic characteristics of the two groups.



Moreover, we did not find any significant differences between the two groups in terms of eating behaviors based on the parents-reported CEBQ results (Table 2). The boys and girls with ADHD were not significantly different in eating behaviors based on the CEBQ scores, except for the satiety responsiveness (t=-2.62, P=0.01). The only significant difference between TD boys and TD girls was in the “slowness in eating” subscale of CEBQ (t=-2.206, P=0.03). In addition, we did not find any gender-related BMI differences in any of the two groups.



The parents in both groups were not different in terms of their parental feeding practice based on the CFPQ scores, except for emotion regulation and monitoring subscales (Table 3).



The association between the BMI and the study variables was calculated separately. Table 4 summarizes the results of calculating the association between the CPRS scores and the BMI in the two groups.




As Table 4 represents, there was a weak negative correlation between mean scores of the BMI and CPRS subscales in children with ADHD. However, the only significant association was related to hyperactivity. We did not find any significant correlations among these variables in the TD group. No significant difference was detected between children’s and parents’ BMI in both groups. The calculation of the correlation between BMI and the CEBQ scale scores in the two groups showed a significant relationship with the first three scales of the questionnaire, including food fussiness (r=-0.281, P=0.006), food enjoyment (r=0.295, P=0.004), food responsiveness/emotional overeating (r=0.288, P=0.005). In the TD group, BMI was positively associated with food enjoyment (r=0.207, P=0.049) and emotional under-eating (r=0.29, P=0.005). However, no significant association was observed between the CFPQ scores and BMI in the two groups, except for limitations for health (r=0.249, P=0.015; r=0.257, P=0.014) and limitations for weight control (r=0.4 , P<0.000; r=0.256, P<0.011) in ADHD and TD group, respectively.
The stepwise regression analysis showed that the only variables which could significantly predict the BMI in the participants were limitations for weight control (β=0.355, P=0.000) and food fussiness (β =-0.230, P=0.001) in the group with ADHD, and limitation for health in the control TD group (β=0.269, P=0.010).

Discussion
The objectives of this study were to compare children’s weight, BMI, and eating behaviors, as well as parental feeding practices between a group of TD children and a group of children with ADHD. In a recent study, the BMI scores of children with ADHD were in the normal range. However, some studies reported obesity and fatness among children with ADHD, showing a significant correlation between eating disorders and the risk of fatness among them [4, 6-8]. Moreover, this study did not find any significant differences between eating behaviors in children with and without ADHD. This was consistent with Şahan et al. study, showing that disinhibited eating did not differ according to the presence of ADHD [22]. However, another study found that children with ADHD had a higher risk of impulsive bulimic eating behavior [1, 5, 6]. In a recent study, a significant weak correlation was detected in the group of ADHD between BMI and emotional overeating score derived from CEBQ along with a negative correlation with the hyperactivity index of CPRS. Some studies found no significant correlation between BMI and ADHD in children [3, 23]. It has been suggested that some variables (such as hyperactivity) in children with ADHD undo weight gain [5, 24]. Parents have a significant effect on children’s pattern of eating behaviors [3]. In the present study, the CFPQ emotion regulation subscale mean score in the ADHD group was higher compared to the TD group. When a child with ADHD is tired, distressed, anxious, or fussy, their parents would feed them when compared to a TD child [3]. The parents of children with ADHD also had lower mean scores in the index of monitoring compared to parents of the TD group; in other words, these parents serve potato crisp, oily foods, sweat drinks, and sweat meats to their children. Besides, Children with ADHD show a loss of control over overeating syndrome, with “overeating” and “craving for food” in response to negative emotional distress [6, 24]. In terms of the causal relationship between children’s characteristics and their parent’s responses, parental feeding practices are affected by their children’s nature [25], even though genetic parental factors may be involved. Meanwhile, indulgent feeding and chronic overeating behaviors lead to fatness. This may be one of the main causes of fatness and obesity among children with ADHD compared to the general population [24, 26]. Although the present investigation did not find any significant differences between the two groups in terms of children’s BMI, the mean score in food fussiness was higher in children with ADHD, proposing that they avoided new tastes and foods compared to the TD group. In a recent study, the parents of the TD children who had higher BMI compared to the other group limited their children to control their health more. Therefore, children without ADHD were less interested and used less nutritive value food products and sweetmeats. This was consistent with a study that reported that dietary restriction was correlated with BMI among children [27, 28]. A systematic review confirmed that children feeding restrictions by parents are correlated with higher BMI, while lower BMI was negatively associated with higher coercive behaviors about feeding practices by parents [26]. 
Study strengths and limitations
This study included both genders while previous investigations were mostly conducted on one gender. The present study’s findings should be considered in light of some limitations. Firstly, this was a cross-sectional study and could not evaluate the causal relationship between variables. Secondly, although BMI is a clinical index of over or underweight, it is not a valid index of adiposity. Thirdly, children’s eating behaviors were just evaluated based on parental reports instead of straight clinical observation. 

Conclusion 
Although children’s weight and BMI are affected by multiple factors, such as eating behaviors and physical activity of the child and parental feeding practices, this study did not find any significant differences between the two groups of children with ADHD and TD children on indexes of nutrition, eating behaviors, and parental feeding practices. Therefore, the assessment of individual differences and familial factors may help determine complicated relations of factors about the incidence of fatness and obesity. It would be helpful to assess confounding variables, such as physical activity and birth weight, as well as use more direct observable tools to check eating-related problems.

Ethical Considerations

Compliance with ethical guidelines
The Ethics Committee of Tehran University of Medical Sciences has approved this study (Code of Ethics: TUMS.MEDICINE.REC.1396.2760).

Funding
This study was done as a dissertation thesis to achieve a subspecialty degree in child and adolescent psychiatry by the Samaneh Farnia at Tehran University of Medical Sciences.

Authors' contributions
Study design and writing the protocol: Javad Alaghband Rad and Zahra Shahrivar; Literature review and summaries, statistical analysis, draftig the manscript: Samaneh Farnia; All authors contributed to prepare the final manuscript and approved the final version.

Conflict of interest
The authors declared no conflict of interest.

Acknowledgments
We are grateful to all children and their parents who participated in the study. Besides, we thank the principals and staff working at the schools who cooperated with the research. 
 

1. Kaisari P, Dourish CT, Higgs S. Attention deficit hyperactivity disorder (ADHD) and disordered eating behaviour: A systematic review and a framework for future research. Clin Psychol Rev. 2017; 53:109-21. [DOI:10.1016/j.cpr.2017.03.002] [PMID]
2. Levin RL, Rawana JS. Attention-deficit/hyperactivity disorder and eating disorders across the lifespan: A systematic review of the literature. Clin Psychol Rev. 2016; 50:22-36. [DOI:10.1016/j.cpr.2016.09.010] [PMID]
3. Tong L Shi H, Li X. Associations among ADHD, Abnormal eating and overweight in a non-clinical sample of Asian children. Sci Rep. 2017; 7(1):2844. [DOI:10.1038/s41598-017-03074-4] [PMID] [PMCID]
4. Nazar BP, Bernardes C, Peachey G, Sergeant J, Mattos P, Treasure J. The risk of eating disorders comorbid with attention-deficit/hyperactivity disorder: A systematic review and meta-analysis. Int J Eat Disord. 2016; 49(12):1045-57. [DOI:10.1002/eat.22643] [PMID]
5. Khalife N, Kantomaa M, Glover V, Tammelin T, Laitinen J, Ebeling H, et al. Childhood attention-deficit/hyperactivity disorder symptoms are risk factors for obesity and physical inactivity in adolescence. J Am Acad Child Adolesc Psychiatry. 2014; 53(4):425-36. [DOI:10.1016/j.jaac.2014.01.009] [PMID]
6. Reinblatt SP, Mahone EM, Tanofsky-Kraff M, Lee-Winn AE, Yenokyan G, Leoutsakos JM, et al. Pediatric loss of control eating syndrome: Association with attention-deficit/hyperactivity disorder and impulsivity. Int J Eat Disord. 2015; 48(6):580-8. [DOI:10.1002/eat.22404] [PMID] [PMCID]
7. Kim EJ, Kwon HJ, Ha M, Lim MH, Oh SY, Kim JH, et al. Relationship among attention-deficit hyperactivity disorder, dietary behaviors and obesity. Child Care Health Dev. 2014; 40(5):698-705. [DOI:10.1111/cch.12129] [PMID]
8. Sonneville KR, Calzo JP, Horton NJ, Field AE, Crosby RD, Solmi F, et al. Childhood hyperactivity/inattention and eating disturbances predict binge eating in adolescence. Psychol Med. 2015; 45(12):2511-20. [DOI:10.1017/S0033291715000148] [PMID] [PMCID]
9. Leventakou V, Herle M, Kampouri M, Margetaki K, Vafeiadi M, Kogevinas M, et al. The longitudinal association of eating behaviour and ADHD symptoms in school age children: A follow-up study in the RHEA cohort. Eur Child Adolesc Psychiatry. 2022; 31(3):511-7. [DOI:10.1007/s00787-021-01720-] [PMID] [PMCID]
10. Rajabi G. [Normalizing the raven coloure progressive matrices test on students of city Ahvaz (Persian)]. Contemp Psychol. 2008; 3(1):23-32. [Link]
11. Kaufman J, Birmaher B, Brent D, Rao U, Flynn C, Moreci P, et al. Schedule for affective disorders and schizophrenia for school-age children-present and lifetime version (K-SADS-PL): Initial reliability and validity data. J Am Acad Child Adolesc Psychiatry. 1997; 36(7):980-8. [DOI:10.1097/00004583-199707000-00021] [PMID]
12. Shahrivar Z, Kousha M, Moallemi S, Tehrani-Doost M, Alaghband-Rad J. The reliability and validity of kiddie-schedule for affective disorders and schizophrenia - present and lifetime version - Persian version. Child Adolesc Ment Health. 2010; 15(2):97-102. [DOI:10.1111/j.1475-3588.2008.00518.x] [PMID]
13. Achenbach TM, McConaughy SH, Howell CT. Child/adolescent behavioural and emotional problems: Implication of cross informant correlations for situational specificity. Psychol Bull. 1987; 101(2):213-32. [DOI:10.1037/0033-2909.101.2.213] [PMID]
14. Zarrabi M, Shahrivar Z, Tehrani Doost M, Khademi M, Zargari Nejad G. Concurrent validity of the behavior rating inventory of executive function in children with attention deficit hyperactivity disorder. Iran J Psychiatry Behav Sci. 2015; 9(1):e213. [DOI:10.17795/ijpbs213] [PMID] [PMCID]
15. Eizenman D, Holub S. Comprehensive feeding practices questionnaire: Validation of a new measure of parental feeding practices. J Pediatr Psychol. 2007; 32(8):960-72. [DOI:10.1093/jpepsy/jsm037] [PMID]
16. Doaei S, Kalantari N, Gholamalizadeh M, Rashidkhani B. [Validating and investigating the reliability of comprehensive feeding practices questionnaire (Persian)]. Zahedan J Res Med Sci. 2013; 15(3):e93066. https://brieflands.com/articles/zjrms-93066.html
17. Wardle J, Guthrie CA, Sanderson S, Rapoport L. Development of the children’s eating behaviour questionnaire. J Child Psychol Psychiatry. 2001; 42(7):963-70 [DOI:10.1111/1469-7610.00792] [PMID]
18. Noohi Sh, Hatami H, Janbozorgi M, Banijamali A. [Efficacy of comprehensive training of health-based parenting skills to mothers on modification of eating behaviors of overweight children (Persian)]. Knowl Health. 2016; 11(3):17-24. [Link]
19. Goodman R. Psychometric properties of the strengths and difficulties questionnaire. J Am Acad Child Adolesc Psychiatry. 2001; 40(11):1337-45. [DOI:10.1097/00004583-200111000-00015] [PMID]
20. Berry JW, Poortinga YH, Segall MH, Dasen PR. Methodological concerns. In: Berry JW, Poortinga YH, Segall MH, Dasen PR, editors. Cross-cultural psychology: Research and applications. Cambridge: Cambridge University Press; 2002. [Link]
21. Shahrivar Z, Tehrani-Doost M, Pakbaz B, Rezaie A, Ahmadi F. Normative data and psychometric properties of the parent and teacher versions of the strengths and difficulties questionnaire (SDQ) in an Iranian community sample. J Res Med Sci. 2009; 14(2):69-77. [PMCID]
22. Şahan E, Zengin Eroğlu M, Sertçelik S. Eating behaviors, depression, and anxiety levels of pre bariatric surgery patients with obesity comorbid with or without Attention deficit and hyperactivity disorder: ADHD or major depression? Which is more related with eating behaviors? Brain Behav. 2021; 11(1):e01915. [DOI:10.1002/brb3.1915] [PMID] [PMCID]
23. Leventakou V, Herle M, Kampouri M, Margetaki K, Vafeiadi M, Kogevinas M, et al. The longitudinal association of eating behaviour and ADHD symptoms in school age children: A follow-up study in the RHEA cohort. Eur Child Adolesc Psychiatry. 2022; 31(3):511-7. [DOI:10.1007/s00787-021-01720-] [PMID] [PMCID]
24. Hanć T, Cortese S. Attention deficit/hyperactivity-disorder and obesity: A review and model of current hypotheses explaining their comorbidity. Neurosci Biobehav Rev. 2018; 92:16-28. [DOI:10.1016/j.neubiorev.2018.05.017] [PMID]
25. Shloim N, Edelson LR, Martin N, Hetherington MM. Parenting styles, feeding styles, feeding practices, and weight status in 4-12-year-old children: A systematic review of the literature. Front Psychol. 2015; 6:1849. [DOI:10.3389/fpsyg.2015.01849] [PMID] [PMCID]
26. Alahmadi RA. The effects of parenting style and feeding style on child weight status: A systematic review [MSc, thesis]. Illinois.: Eastern Illinois University; 2019. [Link]
27. Essawy HE, Abdelgawad AA, Khamis ME, Zakaria A. Study of disturbed eating behaviors in children with attention deficit hyperactivity disorder. Middle East Curr Psychiatry. 2020; 27:8 [DOI:10.1186/s43045-020-0016-5]
28. Pauli-Pott U, Becker K, Albayrak O, Hebebrand J, Pott W. Links between psychopathological symptoms and disordered eating behaviors in overweight/obese youths. Int J Eat Disord. 2014; 46(2):156-63. [DOI:10.1002/eat.22055] [PMID]