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research-article2015
JADXXX10.1177/1087054715576917Journal of Attention DisordersAboul-ata and Amin
Article
The Prevalence of ADHD in Fayoum City (Egypt) Among School-Age Children: Depending on a DSM-5-Based Rating Scale
Journal of Attention Disorders 1–7 © 2015 SAGE Publications Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1087054715576917 jad.sagepub.com
Mohammad A. Aboul-ata1 and Fatma A. Amin2
Abstract Objective: In the present study, we created a new valid rating scale to estimate the prevalence of ADHD among schoolage children in Fayoum City. Method: We conducted two consequential studies (Studies 1 and 2). In Study 1, the sample comprised 106 children. The ages of the sample participants ranged between 6 and 14 years. The purpose of that study was to validate a new Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5)-based ADHD rating scale. In Study 2, the sample consisted of 420 children with ages ranging from 6 to 14 years. We used the new rating scale to estimate the prevalence of ADHD. Results: The first study showed that the new rating scale for ADHD was valid. The second study revealed that the prevalence of ADHD in Fayoum City was 20.5%, with 33.8% among boys and 6.8% among girls. Conclusion: We validated a new ADHD rating scale and estimated the prevalence of ADHD in Fayoum City for the first time in Egypt. (J. of Att. Dis. XXXX; XX(X) XX-XX) Keywords ADHD, prevalence, DSM-5 According to the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association [APA], 2013), the prevalence of ADHD in most cultures is approximately 5% among children. Many risk factors (e.g., temperamental, environmental, genetic, and physiological) are responsible for producing this disorder. Males suffer from ADHD more frequently than females (APA, 2013). ADHD is the most prevalent disorder in childhood (Vaziri, Kashani, & Sorati, 2014) and constitutes the most significant public health problem in the United States (Gapin & Etnier, 2014). Disturbances in functioning, academic achievement failure, and social interaction disabilities are considered to be the most common aspects of ADHD. Children with ADHD may experience social rejection and perform worse than their non-ADHD peers in educational and academic achievement (García, Jara, & Sánchez, 2011; Yousefia, Far, & Abdolahian, 2011). Motor skills disability, attention defect, aggression, and reduction in mental potential may also occur in people with ADHD (Barzegary & Zamini, 2011). Internationally, many researchers have estimated the prevalence of ADHD, specifically among school-age children. In Shiraz (south of Iran), the prevalence of ADHD is 10.1%, with 13.6% among boys and 6.5% among girls (Ghanizadeh, 2008). Moreover, in Tehran (Iran), the prevalence of ADHD is 4.1% for the Inattentive subtype, 4.7%
for the Hyperactivity/Impulsivity subtype, and 1.7% for the Combined subtype (Feiz & Emamipour, 2013). The prevalence of ADHD in the United Kingdom is 8.1%, with 1.5% for the Inattentive subtype, 5% for the Hyperactivity/ Impulsivity subtype, and 1.6% for the Combined subtype (Alloway, Elliott, & Holmes, 2010). The prevalence of ADHD in Metropolitan (the capital of the State of Johor in Malaysia) is 1.61%, with 2.75% among boys and 0.60% among girls (Gomez & Hafetz, 2011). In two states (South Carolina and Oklahoma) of the United States, the prevalence rates of ADHD are 8.7% and 10.6%, respectively (Wolraich et al., 2014). In Italy, the prevalence of ADHD is 7.3% among Italian students (Bianchini et al., 2013). In a French community sample, the overall prevalence of ADHD is 10.6% (Caci, Morin, Bouchez, & Baylé, 2013). In the Arab world, few studies have been published on ADHD. However, a systematic review study using the meta-analysis method estimated the prevalence of ADHD across Arab countries. In these countries, the prevalence of ADHD ranged from 7.4% to 14.8%, ranging from 7.8% to 1
University of Fayoum, Egypt Azza Zidan Experimental School, Fayoum, Egypt
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Corresponding Author: Mohammad A. Aboul-ata, Department of Psychology, University of Fayoum, Faculty of Arts Building, Fayoum 63514, Egypt. Email: [email protected]
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18.3% among boys and 3.5% to 11.4% among girls (Farah et al., 2009). Furthermore, in a descriptive study of the characteristics of ADHD among Omani children, the prevalence was 16% in the overall sample (Al-Sharbati, Zaidan, Dorvlo, & Al-Adawi, 2011). In Lebanon, the prevalence of ADHD among the school-age population was 3.2% overall, with 4.5% among boys and 1.8% among girls (Richa et al., 2014). Accordingly, the prevalence of ADHD in the Arab society in general and in Egypt in particular is still vague, despite the problematic consequences of this disorder. Because of the nature of ADHD and the seriousness of its consequences, the periodic estimation of the prevalence of ADHD has been a critical research aim, specifically in developing countries. In Arab countries, there is an essential need to investigate the epidemiology of ADHD. In this cultural context, estimating the prevalence based on a valid rating scale for ADHD continues to be a valuable goal. Consequently, the aim of the present study is twofold: (a) the validation of an ADHD rating scale based on the DSM-5 criteria in an Egyptian sample and (b) the estimation of the prevalence of ADHD in Fayoum City (Egypt) using the new rating scale.
Study 1: Validation of the ADHD Rating Scale Based on the DSM-5 Diagnostic Criteria The purpose of this study is to validate a rating scale for ADHD to achieve two objectives: (a) constructing a scale that is derived directly from the DSM-5 and (b) estimating the psychometric properties of the scale on a national sample to ensure that cultural effects are reduced and to test the DSM-5 construct of ADHD on a national sample.
Method Participants. The sample of the present study consisted of 106 school-age children: 53 children with ADHD (28 boys and 25 girls) aging between 6 and 14 years (M = 9.36, SD = 1.93), and 53 normal children (24 boys and 29 girls), aging between 6 and 14 years (M = 9.43, SD = 2.16). We selected the ADHD participants from the school-age children across two primary schools in Fayoum City. Then, we screened the participants with ADHD using structured clinical interviews for the DSM-5 diagnostic criteria. This structured interview contained disorders listed under the classification “Neurodevelopmental Disorders” in DSM-5. Next, we selected the normal participants using the same structured clinical interview. The inclusion criterion for the participants with ADHD was the existence of DSM-5 diagnostic criteria for ADHD, and the exclusion criterion was a history or current existence of other neurodevelopmental disorders (comorbidity).The inclusion criteria for the normal participants was the absence of ADHD symptoms or
other neurodevelopmental disorders, and the exclusion criterion was the existence of any neurodevelopmental disorders. To explore whether there were significant differences between the two groups in terms of demographic characteristics, we used a t test and Mann–Whitney statistics. There was no difference between the two groups in terms of ages, t(104) = −.189, p = .850. In addition, there was no difference between the two groups in terms of socioeconomic status (Z = −.543, p = .587). Structure of the scale. We selected the 18 symptoms of the DSM-5 diagnostic criteria of ADHD (9 symptoms for Inattentive and 9 symptoms for Hyperactivity/Impulsivity) as the items of the scale, with the word “often” omitted from every item. We used a 5-point Likert-type scale next to every item (scoring key was never = 0, rarely = 1, sometimes = 2, often = 3, and usually = 4). Translation and cultural adaptation of the scale. We followed Guillemin’s (1993) guidelines to translate and conduct a cultural adaptation of the new scale. First, we selected two Arabic native-speaking translators who were aware of the purpose of the translation process. The translators completed the translation independently, producing two versions of the scale items in Arabic language. Next, we selected another two individuals to perform the back-translation of the scale items into the source language. Conversely, the backward-translators had no prior knowledge of the purpose of the study, and they translated the items independently from one another. The backward-translation produced two versions of the scale items in the source language. We gathered a committee to review the four versions of the scale (two forward and two backward versions) and produce the final version. The committee members were multidisciplinary and aware of ADHD psychopathology. To verify cross-cultural equivalence of the source and final versions, we worked with the committee to examine the semantic, idiomatic, experiential, and conceptual equivalencies in the cultural adaptation procedures. Moreover, we used a pre-test (a probe technique) to check equivalency in the source and final versions. In the probe technique, we conducted in-depth interviews with 60 informants (teachers and parents) to identify what they meant in their replies to every item in the scale. Translation and cultural adaptation yielded modifications of Items 1, 3, 6, and 7. The committee had no recommendations for adding or rejecting items. The final version of the ADHD scale contained 18 items in Arabic. Procedures. The informants rated 106 school-age children (53 ADHD and 53 normal) using the new ADHD rating scale. The diagnostic criteria for ADHD were met if the informants marked six items or more for any subtype (Inattentive or Hyperactivity/Impulsivity) as “often” or “usually.”
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Aboul-ata and Amin We calculated the total score of the scale by summing all item scores according to the scoring key mentioned above.
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We conducted all statistical analyses using SPSS (Released 2009. PASW Statistics for Windows, Version 18.0. Chicago: SPSS Inc.) and Amos (Version 16).
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Diagnostic accuracy. We used the nonparametric receiver operating characteristic (ROC) curve (n = 106; 53 ADHD and 53 normal) to estimate the diagnostic accuracy of the ADHD rating scale. The result showed high sensitivity of the scale; the area under the curve was 0.999 (p < .001), with a 95% confidence interval (cutoff point ≥ 41.50). This result showed that the scale was significantly able to accurately classify groups (true positive disordered and true negative disordered).
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Results and Discussion
Reliability Analysis Inter-rater reliability. We estimated the inter-rater reliability depending on teachers’ and parents’ ratings (n = 106; 53 ADHD and 53 normal) using Cohen’s Kappa = .925 (p < .001). This result revealed that the scale was reliable between the two groups of raters. Internal consistency. We estimated the internal consistency of the scale using Cronbach’s alpha (n = 53 ADHD children). The Cronbach’s alphas were .936, .910, and .896 for the total scale (18 items), Inattentive subscale (9 items), and Hyperactivity/Impulsivity subscale (9 items), respectively. These results revealed that the scale has an excellent internal consistency. Cronbach’s alpha revealed that no items needed to be removed from the total scale or either subscale.
Validity Analysis Construct validity. We tested the two factors model (Inattentive factor and Hyperactivity/Impulsivity factor, n = 53 ADHD children) with confirmatory factor analysis (CFA). To address categorical/ordinal data (Likert-type scoring method) using CFA, we used the Bayesian estimation method (Arbuckle, 2007; Byrne, 2010) and maximum likelihood (ML) as a discrepancy of the estimation. The result revealed that there was no significant difference between the observed data and the model, χ2(134, N = 53) = 147.385, p = .203. The model fit indices showed the following values: goodness of fit index (GFI) = 0.769, normed fit index (NFI) = 0.873, incremental fit index (IFI) = 0.987, comparative fit index (CFI) = 0.987, and root mean square error of approximation (RMSEA) = 0.04. The CFA statistics indicated that the ADHD scale reflected the two-factor model of ADHD. The correlation between the two factors
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Figure 1. The CFA standardized regression weights of 18 items, and the correlation between the inattentive factor (In) and the Hyperactivity/Impulsivity factor (HI) of the new rating scale of ADHD. Note. CFA = confirmatory factor analysis.
(Inattentive and Hyperactivity/Impulsivity) achieved a very good level r(51) = .79, p < .001. The standardized regression weights of the Inattention factor ranged between .77 and .93, and those of the Hyperactivity/Impulsivity factor ranged between .72 and .96 (see Figure 1).
Study 2: Estimating the Prevalence of ADHD in Fayoum City Among SchoolAge Children The purpose of this study was to estimate the prevalence of ADHD among school-age children in Fayoum City and to explore the incidence of the disorder based on demographic characteristics.
Method Participants. To select a representative and reasonable sample of school-age children in Fayoum City, we used a cluster random sampling. The steps of the cluster sampling
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were as follows. (a) We explored most school buildings in the area of Fayoum City. (b) We selected seven schools (clusters) that represented the geographical boundaries. (c) We selected all grades (from 1 to 6) from the selected schools. (d) We selected a class from every grade. (e) We randomly selected 10 children from every class. The sampling method resulted in 420 participants. The children’s ages ranged from 6 to 14 years: The boys included 198 children (50.8%) and the girls included 192 children (49.2%). The boys’ ages were M = 9.04 and SD = 2.06, and the girls’ ages were M = 9.67 and SD = 2.03. The selected participants were from rural (6.4%) and urban (93%) regions. The socioeconomic status of the selected participants included low (27.7%), moderate (52.6%), and high (19.7%) levels. The inclusion criteria were the ages between 6 and 14 years for both boys and girls and random selection by the teachers of the classes. Exclusion criteria were history or current neurological disorders or intellectual disabilities. To calculate the appropriateness of the sample size, we used the following formula: n = Z2P(1 − P)/d2, where n = the sample size, Z = Z statistics for a level of confidence, P = expected prevalence of proportion, and d = precision (Naing, Winn, & Rusli, 2006). To set the formula parameter values, we assumed p (expected prevalence) = 20% (0.2). We calculated d2, where d = Z P(1− P) / n . In addition, Z = 1.96 for a confidence level of 95%. As a result, the sample size of our study should have been 246 school-age children. However, this assumed sample size value is applied if the sampling method is simple or systematic random. Because we used cluster sampling method, we had to double the previous formula result. Consequently, the appropriate sample size was 246 × 2 = 492 school-age children. This result indicates that our sample size is acceptable. Measures. We utilized the new ADHD rating scale to estimate the prevalence of ADHD. The scale contains 18 items that reflect the DSM-5 diagnostic criteria of ADHD with a 5-point Likert-type scoring method. We reported the translation, cultural adaptation, and the psychometric properties of the scale in Study 1. Procedures. We trained the main teachers (informants) of the school classes to use the rating scale. The teachers administered the new ADHD rating scale on the selected participants. The procedures for selecting the children were random. If informants selected six or more items in any subtype as “often” or “usually,” the diagnostic criteria of ADHD were met. We collected the demographic characteristics of the participants from the schools’ records.
Results and Discussion To estimate the prevalence and incidence of ADHD among school-age children, we used descriptive, cross-tabulation,
and chi-square statistics using SPSS software (Version 18). The final number of analyzed participants was 390 of 420 school-age children to estimate the prevalence and incidence. We excluded 30 children because of incomplete data and the exclusion criteria mentioned above. Prevalence in the overall study group. The results showed that the prevalence of ADHD in Fayoum City among school-age children (see Table 1) was 20.5%. The prevalence rates within the Inattentive subtype, the Hyperactivity/Impulsivity subtype, and the Combined subtype were 1.3%, 2.8%, and 16.4%, respectively. Prevalence and incidence by gender. ADHD was more prevalent among boys (33.8%) than among girls (6.8%); the chisquare test showed a significant difference in the incidence of ADHD by gender, χ2(1, N = 390) = 43.80, p < .001. The Inattentive subtype was more prevalent in girls (2.1%) than in boys (0.5%); in the Hyperactivity/Impulsivity subtype, the incidence in boys (5.1%) was higher than in girls (0.5%); and the Combined subtype was more prevalent in boys (28.3%) than in girls (4.2%). The difference by gender in ADHD subtypes was also significant, χ2(3, N = 390) = 52.51, p < .001. Prevalence and incidence by socioeconomic status. The prevalence rates of ADHD based on socioeconomic status were 17.6% in low, 20.5% in moderate, and 24.7% in high socioeconomic status. The results showed that the incidence of ADHD by socioeconomic status has no significant difference, χ2(2, N = 390) = 1.38, p = .501. The Inattentive subtype was more prevalent among students with low socioeconomic status (3.7%) than those with moderate (0.5%) or high (0%) socioeconomic status. However, the Hyperactivity/Impulsivity subtype was more prevalent among students with both high (3.9%) and moderate (3.4%) socioeconomic status than in those with low (0.9%) socioeconomic status. The Combined subtype was more prevalent among students with high socioeconomic status (20.8%) than those with moderate (16.6%) or low (13%) socioeconomic status. There was no significant difference in the incidence of ADHD subtypes by socioeconomic status, χ2(6, N = 390) = 10.84, p = .093. Prevalence and incidence by region. ADHD was more prevalent in the urban region (21.1%) than in the rural region (12%). There was no significant difference between the two regions in terms of the ADHD incidence, χ2(1, N = 390) = 1.18, p = .276. In the rural region, the Combined subtype was more prevalent (8%) than the Inattentive subtype (4%), and no student displayed the Hyperactivity/Impulsivity subtype. In the urban region, the Combined subtype was more prevalent (17%) than the Hyperactivity/Impulsivity subtype (3%), and the least prevalent was the Inattentive subtype
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Aboul-ata and Amin Table 1. The Prevalence of ADHD and Its Subtypes in Fayoum City (Egypt). ADHD subtypes Gender Male Female Socioeconomic status Low Moderate High Regions Urban Rural Ages 6 7 8 9 10 11 12 13 14 Overall
Non-ADHD n (%)
ADHD n (%)
In n (%)
HI n (%)
CT n (%)
131 (66.2) 179 (93.2)
67 (33.8) 13 (6.8)
1 (.5) 4 (2.1)
10 (5.1) 1 (.5)
56 (28.3) 8 (4.2)
89 (82.4) 163 (79.5) 58 (75.3)
19 (17.6) 42 (20.5) 19 (24.7)
4 (3.7) 1 (.5) 0
1 (.9) 7 (3.4) 3 (3.9)
14 (13) 34 (16.6) 16 (20.8)
288 (78.9) 22 (88)
77 (21.1) 3 (12)
4 (1.1) 1 (4)
11 (3) 0
62 (17) 2 (8)
29 (82.9) 25 (78.1) 82 (80.4) 50 (86.2) 29 (85.3) 27 (75) 61 (82.4) 11 (68.8) 2 (66.7) 310 (79.5)
6 (17.1) 7 (21.9) 20 (19.6) 8 (13.8) 5 (14.7) 9 (25) 13 (17.6) 5 (31.3) 1 (33.3) 80 (20.5)
0 2 (6.3) 1 (1) 0 0 0 1 (1.4) 1 (6.3) 0 5 (1.3)
0 0 2 (2) 2 (3.4) 1 (2.9) 3 (8.3) 2 (2.7) 1 (6.3) 0 11 (2.8)
6 (17.1) 5 (15.6) 17 (16.7) 6 (10.3) 4 (11.8) 6 (16.7) 10 (13.5) 9 (56) 1 (33.3) 64 (16.4)
Note. In = Inattentive type, HI = Hyperactivity/Impulsivity type, and CT = Combined type.
(1.1%). The incidence of ADHD subtypes by region showed no significant difference, χ2(3, N = 390) = 3.68, p = .297. Prevalence and incidence by age. The greatest prevalence of ADHD occurred in the 13-year-old students (68.8%), and the lowest prevalence occurred in the 8-year-old students (13.8%). The incidence of ADHD based on age between 6 and 14 years showed a significant difference, χ2(8, N = 390) = 26.61, p = .001. The most prevalent ADHD subtype across all ages was the Combined subtype. The incidence of ADHD subtypes based on age showed a significant difference, χ2(24, N = 390) = 41.93, p = .01.
General Discussion We conducted Study 1 to validate a new rating scale based on the DSM-5 diagnostic criteria. The validation of this new rating scale aimed to (a) reduce the cultural effects on the informant’s understanding of the scale items, (b) examine the construct of the DSM-5 diagnostic criteria for ADHD, and (c) estimate the prevalence of ADHD in an Egyptian sample among school-age children. The psychometric properties of the new rating scale for ADHD showed reliability and validity. The scale showed high accuracy in discriminating true positive disordered and true negative disordered participants. Reliability was demonstrated by high agreement between the two raters and high consistency among the
scale items. A CFA of 18 items loaded on the two factors (Inattention and Hyperactivity–Impulsivity) showed that the model fit the Egyptian sample. Then, we conducted Study 2 to estimate the prevalence of ADHD in Fayoum City (Egypt) among school-age children. The DSM-5 showed that the prevalence of ADHD was approximately 5% in most cultures (APA, 2013). Internationally, the prevalence of ADHD ranges from 1.61% in overall children in countries such as Malaysia (Gomez & Hafetz, 2011) to 10.6%, such as in the state of Oklahoma in the United States (Wolraich et al., 2014) and in a French community sample (Caci et al., 2013). The estimates of ADHD prevalence in the Arab world were higher than the DSM-5 prevalence of ADHD and the international prevalence. In reviewing most of the estimates of ADHD prevalence in the Arab world, we found that it ranges from 3.2% in a Lebanon sample (Richa et al., 2014) to 16% in an Omani sample of children (Al-Sharbati et al., 2011). The ADHD prevalence in Fayoum City (20.5%), however, was the highest in comparison with the DSM-5 both internationally and in the Arab countries. The inattentive subtype and Hyperactivity/Impulsivity subtype prevalence rates in Fayoum City reached the same prevalence in the international and other Arab countries. However, the Combined subtype exceeded the other levels (16.4%) and formed a greater portion of the overall prevalence in Fayoum City.
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The results also showed that ADHD was more prevalent in students with high socioeconomic status than low and moderate ones, and the Inattentive subtype was more apparent in students at a low socioeconomic level than those at a moderate and high socioeconomic level. However, despite the existence of differences in the prevalence of ADHD among socioeconomic levels, these differences did not reach a significant level in this study. The results of the present study agreed with another study conducted in Iran, which revealed that the prevalence of ADHD did not significantly differ among socioeconomic status (Jahangard, Haghighi, Bajoghli, Holsboer-Trachsler, & Brand, 2013). The participants in the urban region suffered ADHD more frequently than those from the rural region did. However, there was no significant difference between the two regions. In exploring the differences among children’s ages in the incidence of ADHD, students who were 13 years old had the greatest incidence in this study sample. Students who were 8 years old had the lowest ADHD prevalence among the others. We found significant differences among ages between 6 and 14 years in terms of ADHD prevalence. Moreover, the high identification rate of ADHD in our sample may have resulted from the fact that we only used teachers as informants and excluded the parents. Furthermore, our inclusion of a broad range of ages between 6 and 14 years could also account for the high prevalence, as shown by our participants at the age of 13, who represented a great portion of overall prevalence in our sample. Gender plays a major role in epidemiology of ADHD and its subtypes (Almagor, Joseph, Ansari, & Subramaniam, 2011). Because ADHD is more prevalent in boys than in girls, methods that include unequal gender samples may reveal inaccurate prevalences. As a result, the gender equality in our sample may have led to such a high prevalence of ADHD when compared with samples that contained unequal gender with high proportions of girls.
Summary and Conclusion We developed a new rating scale for ADHD based on the DSM-5 to estimate the prevalence of ADHD. The results of the overall prevalence showed a higher prevalence in Fayoum City among school-age children in comparison with the DSM-5, international, and the Arab world prevalence rates. This high prevalence may have stemmed from the gender equality and the broad range of ages in our study. Furthermore, using rating scales and one type of informants (teachers rather than parents) often resulted in a higher prevalence than using structured clinical interviews and the common two types of informants. Generally, we found consistency in our study with a literature review that found that ADHD is more frequent in boys than in girls and that the inattentive type appeared in girls more than in boys. In addition, both the Hyperactivity/ Impulsivity and Combined subtypes were more prevalent
in boys than in girls. In our study, significant differences in ADHD prevalence appeared only between gender and among ages. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
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Author Biographies Mohammad A. Aboul-ata, PhD, is a lecturer of clinical psychology in the Department of Psychology at the University of Fayoum in Fayoum, Egypt. Fatma A. Amin, BA, is freshly graduated from the University of Fayoum and worked as a school psychologist at Azaa Zidan Experimental School in Fayoum, Egypt.
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research-article2015
JADXXX10.1177/1087054715576917Journal of Attention DisordersAboul-ata and Amin
Article
The Prevalence of ADHD in Fayoum City (Egypt) Among School-Age Children: Depending on a DSM-5-Based Rating Scale
Journal of Attention Disorders 1–7 © 2015 SAGE Publications Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1087054715576917 jad.sagepub.com
Mohammad A. Aboul-ata1 and Fatma A. Amin2
Abstract Objective: In the present study, we created a new valid rating scale to estimate the prevalence of ADHD among schoolage children in Fayoum City. Method: We conducted two consequential studies (Studies 1 and 2). In Study 1, the sample comprised 106 children. The ages of the sample participants ranged between 6 and 14 years. The purpose of that study was to validate a new Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5)-based ADHD rating scale. In Study 2, the sample consisted of 420 children with ages ranging from 6 to 14 years. We used the new rating scale to estimate the prevalence of ADHD. Results: The first study showed that the new rating scale for ADHD was valid. The second study revealed that the prevalence of ADHD in Fayoum City was 20.5%, with 33.8% among boys and 6.8% among girls. Conclusion: We validated a new ADHD rating scale and estimated the prevalence of ADHD in Fayoum City for the first time in Egypt. (J. of Att. Dis. XXXX; XX(X) XX-XX) Keywords ADHD, prevalence, DSM-5 According to the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association [APA], 2013), the prevalence of ADHD in most cultures is approximately 5% among children. Many risk factors (e.g., temperamental, environmental, genetic, and physiological) are responsible for producing this disorder. Males suffer from ADHD more frequently than females (APA, 2013). ADHD is the most prevalent disorder in childhood (Vaziri, Kashani, & Sorati, 2014) and constitutes the most significant public health problem in the United States (Gapin & Etnier, 2014). Disturbances in functioning, academic achievement failure, and social interaction disabilities are considered to be the most common aspects of ADHD. Children with ADHD may experience social rejection and perform worse than their non-ADHD peers in educational and academic achievement (García, Jara, & Sánchez, 2011; Yousefia, Far, & Abdolahian, 2011). Motor skills disability, attention defect, aggression, and reduction in mental potential may also occur in people with ADHD (Barzegary & Zamini, 2011). Internationally, many researchers have estimated the prevalence of ADHD, specifically among school-age children. In Shiraz (south of Iran), the prevalence of ADHD is 10.1%, with 13.6% among boys and 6.5% among girls (Ghanizadeh, 2008). Moreover, in Tehran (Iran), the prevalence of ADHD is 4.1% for the Inattentive subtype, 4.7%
for the Hyperactivity/Impulsivity subtype, and 1.7% for the Combined subtype (Feiz & Emamipour, 2013). The prevalence of ADHD in the United Kingdom is 8.1%, with 1.5% for the Inattentive subtype, 5% for the Hyperactivity/ Impulsivity subtype, and 1.6% for the Combined subtype (Alloway, Elliott, & Holmes, 2010). The prevalence of ADHD in Metropolitan (the capital of the State of Johor in Malaysia) is 1.61%, with 2.75% among boys and 0.60% among girls (Gomez & Hafetz, 2011). In two states (South Carolina and Oklahoma) of the United States, the prevalence rates of ADHD are 8.7% and 10.6%, respectively (Wolraich et al., 2014). In Italy, the prevalence of ADHD is 7.3% among Italian students (Bianchini et al., 2013). In a French community sample, the overall prevalence of ADHD is 10.6% (Caci, Morin, Bouchez, & Baylé, 2013). In the Arab world, few studies have been published on ADHD. However, a systematic review study using the meta-analysis method estimated the prevalence of ADHD across Arab countries. In these countries, the prevalence of ADHD ranged from 7.4% to 14.8%, ranging from 7.8% to 1
University of Fayoum, Egypt Azza Zidan Experimental School, Fayoum, Egypt
2
Corresponding Author: Mohammad A. Aboul-ata, Department of Psychology, University of Fayoum, Faculty of Arts Building, Fayoum 63514, Egypt. Email: [email protected]
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18.3% among boys and 3.5% to 11.4% among girls (Farah et al., 2009). Furthermore, in a descriptive study of the characteristics of ADHD among Omani children, the prevalence was 16% in the overall sample (Al-Sharbati, Zaidan, Dorvlo, & Al-Adawi, 2011). In Lebanon, the prevalence of ADHD among the school-age population was 3.2% overall, with 4.5% among boys and 1.8% among girls (Richa et al., 2014). Accordingly, the prevalence of ADHD in the Arab society in general and in Egypt in particular is still vague, despite the problematic consequences of this disorder. Because of the nature of ADHD and the seriousness of its consequences, the periodic estimation of the prevalence of ADHD has been a critical research aim, specifically in developing countries. In Arab countries, there is an essential need to investigate the epidemiology of ADHD. In this cultural context, estimating the prevalence based on a valid rating scale for ADHD continues to be a valuable goal. Consequently, the aim of the present study is twofold: (a) the validation of an ADHD rating scale based on the DSM-5 criteria in an Egyptian sample and (b) the estimation of the prevalence of ADHD in Fayoum City (Egypt) using the new rating scale.
Study 1: Validation of the ADHD Rating Scale Based on the DSM-5 Diagnostic Criteria The purpose of this study is to validate a rating scale for ADHD to achieve two objectives: (a) constructing a scale that is derived directly from the DSM-5 and (b) estimating the psychometric properties of the scale on a national sample to ensure that cultural effects are reduced and to test the DSM-5 construct of ADHD on a national sample.
Method Participants. The sample of the present study consisted of 106 school-age children: 53 children with ADHD (28 boys and 25 girls) aging between 6 and 14 years (M = 9.36, SD = 1.93), and 53 normal children (24 boys and 29 girls), aging between 6 and 14 years (M = 9.43, SD = 2.16). We selected the ADHD participants from the school-age children across two primary schools in Fayoum City. Then, we screened the participants with ADHD using structured clinical interviews for the DSM-5 diagnostic criteria. This structured interview contained disorders listed under the classification “Neurodevelopmental Disorders” in DSM-5. Next, we selected the normal participants using the same structured clinical interview. The inclusion criterion for the participants with ADHD was the existence of DSM-5 diagnostic criteria for ADHD, and the exclusion criterion was a history or current existence of other neurodevelopmental disorders (comorbidity).The inclusion criteria for the normal participants was the absence of ADHD symptoms or
other neurodevelopmental disorders, and the exclusion criterion was the existence of any neurodevelopmental disorders. To explore whether there were significant differences between the two groups in terms of demographic characteristics, we used a t test and Mann–Whitney statistics. There was no difference between the two groups in terms of ages, t(104) = −.189, p = .850. In addition, there was no difference between the two groups in terms of socioeconomic status (Z = −.543, p = .587). Structure of the scale. We selected the 18 symptoms of the DSM-5 diagnostic criteria of ADHD (9 symptoms for Inattentive and 9 symptoms for Hyperactivity/Impulsivity) as the items of the scale, with the word “often” omitted from every item. We used a 5-point Likert-type scale next to every item (scoring key was never = 0, rarely = 1, sometimes = 2, often = 3, and usually = 4). Translation and cultural adaptation of the scale. We followed Guillemin’s (1993) guidelines to translate and conduct a cultural adaptation of the new scale. First, we selected two Arabic native-speaking translators who were aware of the purpose of the translation process. The translators completed the translation independently, producing two versions of the scale items in Arabic language. Next, we selected another two individuals to perform the back-translation of the scale items into the source language. Conversely, the backward-translators had no prior knowledge of the purpose of the study, and they translated the items independently from one another. The backward-translation produced two versions of the scale items in the source language. We gathered a committee to review the four versions of the scale (two forward and two backward versions) and produce the final version. The committee members were multidisciplinary and aware of ADHD psychopathology. To verify cross-cultural equivalence of the source and final versions, we worked with the committee to examine the semantic, idiomatic, experiential, and conceptual equivalencies in the cultural adaptation procedures. Moreover, we used a pre-test (a probe technique) to check equivalency in the source and final versions. In the probe technique, we conducted in-depth interviews with 60 informants (teachers and parents) to identify what they meant in their replies to every item in the scale. Translation and cultural adaptation yielded modifications of Items 1, 3, 6, and 7. The committee had no recommendations for adding or rejecting items. The final version of the ADHD scale contained 18 items in Arabic. Procedures. The informants rated 106 school-age children (53 ADHD and 53 normal) using the new ADHD rating scale. The diagnostic criteria for ADHD were met if the informants marked six items or more for any subtype (Inattentive or Hyperactivity/Impulsivity) as “often” or “usually.”
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Aboul-ata and Amin We calculated the total score of the scale by summing all item scores according to the scoring key mentioned above.
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We conducted all statistical analyses using SPSS (Released 2009. PASW Statistics for Windows, Version 18.0. Chicago: SPSS Inc.) and Amos (Version 16).
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Diagnostic accuracy. We used the nonparametric receiver operating characteristic (ROC) curve (n = 106; 53 ADHD and 53 normal) to estimate the diagnostic accuracy of the ADHD rating scale. The result showed high sensitivity of the scale; the area under the curve was 0.999 (p < .001), with a 95% confidence interval (cutoff point ≥ 41.50). This result showed that the scale was significantly able to accurately classify groups (true positive disordered and true negative disordered).
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Results and Discussion
Reliability Analysis Inter-rater reliability. We estimated the inter-rater reliability depending on teachers’ and parents’ ratings (n = 106; 53 ADHD and 53 normal) using Cohen’s Kappa = .925 (p < .001). This result revealed that the scale was reliable between the two groups of raters. Internal consistency. We estimated the internal consistency of the scale using Cronbach’s alpha (n = 53 ADHD children). The Cronbach’s alphas were .936, .910, and .896 for the total scale (18 items), Inattentive subscale (9 items), and Hyperactivity/Impulsivity subscale (9 items), respectively. These results revealed that the scale has an excellent internal consistency. Cronbach’s alpha revealed that no items needed to be removed from the total scale or either subscale.
Validity Analysis Construct validity. We tested the two factors model (Inattentive factor and Hyperactivity/Impulsivity factor, n = 53 ADHD children) with confirmatory factor analysis (CFA). To address categorical/ordinal data (Likert-type scoring method) using CFA, we used the Bayesian estimation method (Arbuckle, 2007; Byrne, 2010) and maximum likelihood (ML) as a discrepancy of the estimation. The result revealed that there was no significant difference between the observed data and the model, χ2(134, N = 53) = 147.385, p = .203. The model fit indices showed the following values: goodness of fit index (GFI) = 0.769, normed fit index (NFI) = 0.873, incremental fit index (IFI) = 0.987, comparative fit index (CFI) = 0.987, and root mean square error of approximation (RMSEA) = 0.04. The CFA statistics indicated that the ADHD scale reflected the two-factor model of ADHD. The correlation between the two factors
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Figure 1. The CFA standardized regression weights of 18 items, and the correlation between the inattentive factor (In) and the Hyperactivity/Impulsivity factor (HI) of the new rating scale of ADHD. Note. CFA = confirmatory factor analysis.
(Inattentive and Hyperactivity/Impulsivity) achieved a very good level r(51) = .79, p < .001. The standardized regression weights of the Inattention factor ranged between .77 and .93, and those of the Hyperactivity/Impulsivity factor ranged between .72 and .96 (see Figure 1).
Study 2: Estimating the Prevalence of ADHD in Fayoum City Among SchoolAge Children The purpose of this study was to estimate the prevalence of ADHD among school-age children in Fayoum City and to explore the incidence of the disorder based on demographic characteristics.
Method Participants. To select a representative and reasonable sample of school-age children in Fayoum City, we used a cluster random sampling. The steps of the cluster sampling
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were as follows. (a) We explored most school buildings in the area of Fayoum City. (b) We selected seven schools (clusters) that represented the geographical boundaries. (c) We selected all grades (from 1 to 6) from the selected schools. (d) We selected a class from every grade. (e) We randomly selected 10 children from every class. The sampling method resulted in 420 participants. The children’s ages ranged from 6 to 14 years: The boys included 198 children (50.8%) and the girls included 192 children (49.2%). The boys’ ages were M = 9.04 and SD = 2.06, and the girls’ ages were M = 9.67 and SD = 2.03. The selected participants were from rural (6.4%) and urban (93%) regions. The socioeconomic status of the selected participants included low (27.7%), moderate (52.6%), and high (19.7%) levels. The inclusion criteria were the ages between 6 and 14 years for both boys and girls and random selection by the teachers of the classes. Exclusion criteria were history or current neurological disorders or intellectual disabilities. To calculate the appropriateness of the sample size, we used the following formula: n = Z2P(1 − P)/d2, where n = the sample size, Z = Z statistics for a level of confidence, P = expected prevalence of proportion, and d = precision (Naing, Winn, & Rusli, 2006). To set the formula parameter values, we assumed p (expected prevalence) = 20% (0.2). We calculated d2, where d = Z P(1− P) / n . In addition, Z = 1.96 for a confidence level of 95%. As a result, the sample size of our study should have been 246 school-age children. However, this assumed sample size value is applied if the sampling method is simple or systematic random. Because we used cluster sampling method, we had to double the previous formula result. Consequently, the appropriate sample size was 246 × 2 = 492 school-age children. This result indicates that our sample size is acceptable. Measures. We utilized the new ADHD rating scale to estimate the prevalence of ADHD. The scale contains 18 items that reflect the DSM-5 diagnostic criteria of ADHD with a 5-point Likert-type scoring method. We reported the translation, cultural adaptation, and the psychometric properties of the scale in Study 1. Procedures. We trained the main teachers (informants) of the school classes to use the rating scale. The teachers administered the new ADHD rating scale on the selected participants. The procedures for selecting the children were random. If informants selected six or more items in any subtype as “often” or “usually,” the diagnostic criteria of ADHD were met. We collected the demographic characteristics of the participants from the schools’ records.
Results and Discussion To estimate the prevalence and incidence of ADHD among school-age children, we used descriptive, cross-tabulation,
and chi-square statistics using SPSS software (Version 18). The final number of analyzed participants was 390 of 420 school-age children to estimate the prevalence and incidence. We excluded 30 children because of incomplete data and the exclusion criteria mentioned above. Prevalence in the overall study group. The results showed that the prevalence of ADHD in Fayoum City among school-age children (see Table 1) was 20.5%. The prevalence rates within the Inattentive subtype, the Hyperactivity/Impulsivity subtype, and the Combined subtype were 1.3%, 2.8%, and 16.4%, respectively. Prevalence and incidence by gender. ADHD was more prevalent among boys (33.8%) than among girls (6.8%); the chisquare test showed a significant difference in the incidence of ADHD by gender, χ2(1, N = 390) = 43.80, p < .001. The Inattentive subtype was more prevalent in girls (2.1%) than in boys (0.5%); in the Hyperactivity/Impulsivity subtype, the incidence in boys (5.1%) was higher than in girls (0.5%); and the Combined subtype was more prevalent in boys (28.3%) than in girls (4.2%). The difference by gender in ADHD subtypes was also significant, χ2(3, N = 390) = 52.51, p < .001. Prevalence and incidence by socioeconomic status. The prevalence rates of ADHD based on socioeconomic status were 17.6% in low, 20.5% in moderate, and 24.7% in high socioeconomic status. The results showed that the incidence of ADHD by socioeconomic status has no significant difference, χ2(2, N = 390) = 1.38, p = .501. The Inattentive subtype was more prevalent among students with low socioeconomic status (3.7%) than those with moderate (0.5%) or high (0%) socioeconomic status. However, the Hyperactivity/Impulsivity subtype was more prevalent among students with both high (3.9%) and moderate (3.4%) socioeconomic status than in those with low (0.9%) socioeconomic status. The Combined subtype was more prevalent among students with high socioeconomic status (20.8%) than those with moderate (16.6%) or low (13%) socioeconomic status. There was no significant difference in the incidence of ADHD subtypes by socioeconomic status, χ2(6, N = 390) = 10.84, p = .093. Prevalence and incidence by region. ADHD was more prevalent in the urban region (21.1%) than in the rural region (12%). There was no significant difference between the two regions in terms of the ADHD incidence, χ2(1, N = 390) = 1.18, p = .276. In the rural region, the Combined subtype was more prevalent (8%) than the Inattentive subtype (4%), and no student displayed the Hyperactivity/Impulsivity subtype. In the urban region, the Combined subtype was more prevalent (17%) than the Hyperactivity/Impulsivity subtype (3%), and the least prevalent was the Inattentive subtype
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Aboul-ata and Amin Table 1. The Prevalence of ADHD and Its Subtypes in Fayoum City (Egypt). ADHD subtypes Gender Male Female Socioeconomic status Low Moderate High Regions Urban Rural Ages 6 7 8 9 10 11 12 13 14 Overall
Non-ADHD n (%)
ADHD n (%)
In n (%)
HI n (%)
CT n (%)
131 (66.2) 179 (93.2)
67 (33.8) 13 (6.8)
1 (.5) 4 (2.1)
10 (5.1) 1 (.5)
56 (28.3) 8 (4.2)
89 (82.4) 163 (79.5) 58 (75.3)
19 (17.6) 42 (20.5) 19 (24.7)
4 (3.7) 1 (.5) 0
1 (.9) 7 (3.4) 3 (3.9)
14 (13) 34 (16.6) 16 (20.8)
288 (78.9) 22 (88)
77 (21.1) 3 (12)
4 (1.1) 1 (4)
11 (3) 0
62 (17) 2 (8)
29 (82.9) 25 (78.1) 82 (80.4) 50 (86.2) 29 (85.3) 27 (75) 61 (82.4) 11 (68.8) 2 (66.7) 310 (79.5)
6 (17.1) 7 (21.9) 20 (19.6) 8 (13.8) 5 (14.7) 9 (25) 13 (17.6) 5 (31.3) 1 (33.3) 80 (20.5)
0 2 (6.3) 1 (1) 0 0 0 1 (1.4) 1 (6.3) 0 5 (1.3)
0 0 2 (2) 2 (3.4) 1 (2.9) 3 (8.3) 2 (2.7) 1 (6.3) 0 11 (2.8)
6 (17.1) 5 (15.6) 17 (16.7) 6 (10.3) 4 (11.8) 6 (16.7) 10 (13.5) 9 (56) 1 (33.3) 64 (16.4)
Note. In = Inattentive type, HI = Hyperactivity/Impulsivity type, and CT = Combined type.
(1.1%). The incidence of ADHD subtypes by region showed no significant difference, χ2(3, N = 390) = 3.68, p = .297. Prevalence and incidence by age. The greatest prevalence of ADHD occurred in the 13-year-old students (68.8%), and the lowest prevalence occurred in the 8-year-old students (13.8%). The incidence of ADHD based on age between 6 and 14 years showed a significant difference, χ2(8, N = 390) = 26.61, p = .001. The most prevalent ADHD subtype across all ages was the Combined subtype. The incidence of ADHD subtypes based on age showed a significant difference, χ2(24, N = 390) = 41.93, p = .01.
General Discussion We conducted Study 1 to validate a new rating scale based on the DSM-5 diagnostic criteria. The validation of this new rating scale aimed to (a) reduce the cultural effects on the informant’s understanding of the scale items, (b) examine the construct of the DSM-5 diagnostic criteria for ADHD, and (c) estimate the prevalence of ADHD in an Egyptian sample among school-age children. The psychometric properties of the new rating scale for ADHD showed reliability and validity. The scale showed high accuracy in discriminating true positive disordered and true negative disordered participants. Reliability was demonstrated by high agreement between the two raters and high consistency among the
scale items. A CFA of 18 items loaded on the two factors (Inattention and Hyperactivity–Impulsivity) showed that the model fit the Egyptian sample. Then, we conducted Study 2 to estimate the prevalence of ADHD in Fayoum City (Egypt) among school-age children. The DSM-5 showed that the prevalence of ADHD was approximately 5% in most cultures (APA, 2013). Internationally, the prevalence of ADHD ranges from 1.61% in overall children in countries such as Malaysia (Gomez & Hafetz, 2011) to 10.6%, such as in the state of Oklahoma in the United States (Wolraich et al., 2014) and in a French community sample (Caci et al., 2013). The estimates of ADHD prevalence in the Arab world were higher than the DSM-5 prevalence of ADHD and the international prevalence. In reviewing most of the estimates of ADHD prevalence in the Arab world, we found that it ranges from 3.2% in a Lebanon sample (Richa et al., 2014) to 16% in an Omani sample of children (Al-Sharbati et al., 2011). The ADHD prevalence in Fayoum City (20.5%), however, was the highest in comparison with the DSM-5 both internationally and in the Arab countries. The inattentive subtype and Hyperactivity/Impulsivity subtype prevalence rates in Fayoum City reached the same prevalence in the international and other Arab countries. However, the Combined subtype exceeded the other levels (16.4%) and formed a greater portion of the overall prevalence in Fayoum City.
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The results also showed that ADHD was more prevalent in students with high socioeconomic status than low and moderate ones, and the Inattentive subtype was more apparent in students at a low socioeconomic level than those at a moderate and high socioeconomic level. However, despite the existence of differences in the prevalence of ADHD among socioeconomic levels, these differences did not reach a significant level in this study. The results of the present study agreed with another study conducted in Iran, which revealed that the prevalence of ADHD did not significantly differ among socioeconomic status (Jahangard, Haghighi, Bajoghli, Holsboer-Trachsler, & Brand, 2013). The participants in the urban region suffered ADHD more frequently than those from the rural region did. However, there was no significant difference between the two regions. In exploring the differences among children’s ages in the incidence of ADHD, students who were 13 years old had the greatest incidence in this study sample. Students who were 8 years old had the lowest ADHD prevalence among the others. We found significant differences among ages between 6 and 14 years in terms of ADHD prevalence. Moreover, the high identification rate of ADHD in our sample may have resulted from the fact that we only used teachers as informants and excluded the parents. Furthermore, our inclusion of a broad range of ages between 6 and 14 years could also account for the high prevalence, as shown by our participants at the age of 13, who represented a great portion of overall prevalence in our sample. Gender plays a major role in epidemiology of ADHD and its subtypes (Almagor, Joseph, Ansari, & Subramaniam, 2011). Because ADHD is more prevalent in boys than in girls, methods that include unequal gender samples may reveal inaccurate prevalences. As a result, the gender equality in our sample may have led to such a high prevalence of ADHD when compared with samples that contained unequal gender with high proportions of girls.
Summary and Conclusion We developed a new rating scale for ADHD based on the DSM-5 to estimate the prevalence of ADHD. The results of the overall prevalence showed a higher prevalence in Fayoum City among school-age children in comparison with the DSM-5, international, and the Arab world prevalence rates. This high prevalence may have stemmed from the gender equality and the broad range of ages in our study. Furthermore, using rating scales and one type of informants (teachers rather than parents) often resulted in a higher prevalence than using structured clinical interviews and the common two types of informants. Generally, we found consistency in our study with a literature review that found that ADHD is more frequent in boys than in girls and that the inattentive type appeared in girls more than in boys. In addition, both the Hyperactivity/ Impulsivity and Combined subtypes were more prevalent
in boys than in girls. In our study, significant differences in ADHD prevalence appeared only between gender and among ages. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
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Author Biographies Mohammad A. Aboul-ata, PhD, is a lecturer of clinical psychology in the Department of Psychology at the University of Fayoum in Fayoum, Egypt. Fatma A. Amin, BA, is freshly graduated from the University of Fayoum and worked as a school psychologist at Azaa Zidan Experimental School in Fayoum, Egypt.
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