Comorbidity & socioeconomic status associated with attention deficit hyperactive disorder

Aims & Objectives: (1) To find out the prevalence of ADHD in urban primary school children (2)To find out the presence of any co-morbid disorders associated with ADHD. Settings and design: This is a cross sectional study of school children selected from 15 different Govt. Schools nearby Govt. Royapettah Hospital, attached to Govt. Kilpauk medical college, Chennai. Material & Methods: 1000 children aged between 5 and 11 years were randomly selected from 15 different schools in Chennai. The presence of ADHD was then assessed by using Vanderbilt assessment scale Teacher’s version by their class teachers. Those children screened positive were verified and reassessed for the presence of any comorbid factors by using Child Behavioural Checklist (CBCL) scale. All children screened positive were subjected to psychiatrist evaluation. Results: The prevalence of ADHD among urban primary school children in Chennai, Tamilnadu was found to be 9.67%. Poor academic performance was the most common associated comorbid condition (18.75%), followed by poor social behaviour (17.7%). Conclusion: The present study shows Poor academic performance was the most common associated comorbid conditions, followed by poor social behaviour.


Introduction
ADHD is characterised by a pattern of diminished sustained attention, hyperactivity and higher level of impulsivity in a child or adolescent which are not appropriate for someone of that age and development. The abnormality of the symptoms must be statistically inappropriate for the child's age, developmental level and duration of the symptoms must be present for at least six months [1]. Thought it is childhood disorder it may continue into adulthood [2].
Research in ADHD is in its nascent stage in India [3]. Venkata J A et al [1] in 2013 screened 770 primary school children aged 6 to 11years at Coimbatore, prevalence of ADHD was found to be 11.32% with higher prevalence among males [66.7%] compared to females [33.3%]. The prevalence was found to be higher among lower socioeconomic status [16.33%] compared to middle socioeconomic group [6.84%] children. Compared with non-ADHD peers, ADHD affected persons are at greater risk for substance abuse  [4], antisocial behaviour, learning and reading disabilities [5], anxiety, mood disorders [6] extending into their adolescence and adulthood. In general, the high frequency of associated comorbid illness has been argued to reflect the heterogenicity of ADHD itself. Hence this disorder places substantial demand on mental health, educational, and judicial services.
Prabhjot Malhi et al [3] in 1999, have done a study on spectrum of ADHD among psychiatric outpatient referrals, they concluded that ADHD is one of the highly prevalent psychiatric disorder in childhood with significant functional impairment. Recognition of these associated comorbid conditions carries important implications for assessment, treatment approaches, and prognosis. Even though ADHD can be diagnosed in preschoolers, most of the cases are referred for assessment only after their behaviour create problems in school.
With this background we screened government school children for ADHD, to identify the comorbid conditions among the affected children. This might enable us to stress the importance of early screening of school

Material and Methods
This study is a descriptive type of study done at Govt. Kilpauk Medical College and Govt. Royapettah Hospital, Department of Paediatrics. The study protocol was approved by Ethical Committee for research studies of Govt. Kilpauk Medical College and Hospital.

Study design: Cross sectional study
Study population: School children in the Government schools in and around Govt. Royapettah Hospital, Chennai were included in the study. These schools cater mainly to urban lower and middle socioeconomic group of children in Chennai.
Sample size: 1000 School going children aged between 5 and 11 were selected from 15 different schools in Chennai District.
Inclusion criteria: Children between the age group of 5 to 11 years.

Exclusion criteria
1. Children with history of seizures/developmental delay.
2. Children with history of neurologic illness/endocrine disorders.
3. Children with history of chronic illness/prolonged drug intake.

Tools used in the study (1) Vanderbilt Assessment Scale-Teacher's version [7]
: This is a rating scale based on DSM diagnostic criteria for ADHD. It consists of several behaviour parameters. This scale is rated by teachers. The scale has two components: symptom assessment and impairment in performance. The symptom assessment screens for symptoms that meet criteria for both inattentive (items 1-9) and hyperactive ADHD (items [10][11][12][13][14][15][16][17][18]. To meet the criteria for the diagnosis, one must have at least 6 positive responses to either the inattentive 9 or hyperactive 9 core symptoms, or both. A positive response is a 2 or 3(often or very often).
The second section of scale has a set of performance questions (36-43), scored 1-5, with 4 and 5 being somewhat of a problem/problematic. To meet the criteria for ADHD there must be at least one item of the performance set in which the child scores a 4 or 5; that is there must be impairment, not just symptoms to meet diagnostic criteria. The initial scales also have symptom screens for 3 other comorbidities such as oppositional defiant, conduct, anxiety and depression. They must score a 2 or 3 out of 10 items on questions 19-28 and score 4 or 5 on any of the performance questions 36-43 to meet screen for oppositional-defiant/conduct disorder. For anxiety/depression screen, must score a 2 or 3 on 3 out of 7 items on questions 29-35 and score a 4 or 5 on any of the performance questions 36-43.

(2) Child Behaviour Check list (CBCL) Scale [8]:
This scale is used to assess the presence of co-morbid factors, social behaviour and academic performance of those children, who were identified having ADHD. The filled up questionnaire was then analysed and those children screened positive were instructed to attend the hospital with their parents. Children with impaired assessment were verified and reassessed for the presence of any comorbid factors by using Child Behavioural Checklist (CBCL) scale, the information for which was sought from their parents by means of a questionnaire in the outpatient department. All children screened positive were subjected to psychiatrist evaluation for a final confirmation of diagnosis and further management. Children diagnosed with ADHD were referred to child guidance clinic for followup.

Results
Among 1000 school children screened 120 children were positive; i.e [12%] of the screened. 96 of these positively screened children were confirmed by the psychiatrist to have ADHD (Table I). The prevalence of ADHD in this study was 9.67%. The most affected age group is between 10 -11 years [21.4%] (Table II). The prevalence of ADHD is 2.7 times more common in males than females (Table III). In this study, the most common subtype was the combined subtype [45.83%] followed by attention deficit [36.46%] and hypertensive impulsive type [17.71%]. The prevalence of ADHD is more in children from lower socioeconomic group 11% compared to middle socioeconomic group (Table IV).
In the affected children comorbidities were present in 60.42% (Table V). Most of the children (77.59%) had only one associated comorbidity and 22.41% of them had two or more comorbid conditions (Table VI) Poor academic performance (18.75%) and poor social behaviour were the most frequently observed co morbidities (Table VII).

Discussion
ADHD is characterised by a pattern of diminished sustained attention, hyperactivity and higher level of impulsivity which are not appropriate for the age and development. The prevalence of ADHD in this study was 9.67%, consistent with that of several studies which showed a wide range of prevalence rates ranging from 2% to 17 % [3,9,10,11]. ADHD affects the interplay of biological, social and psychological factors. There is no definite etiology for ADHD. There are various studies suggesting different contributing factors for ADHD including perinatal mechanic insult to fetal nervous system, perinatal toxic exposure, prematurity, food additives, refined sugar, food allergens, family dysfunction [12,13].
Prevalence of ADHD was found to be highest among children in the age group of 10 -11 years in our study which is validated by several studies showing that children with a mean age of 9 -11 years were the most affected by ADHD [14,15,16,17]. ADHD is more prevalent among the male children compared to female [3,11,18], which is proven in our study as well. According to DSM V, there are 3 subtypes of ADHD: predominantly inattentive type, predominantly hyperactive / impulsive type and combined type. In this study combined type is predominant (45-83%); consistent with previous study done by Pingali et all [18]. The prevalence among middle and lower socioeconomic status is more than upper class; this difference to be highly significant. Venkata JAet al [1] also reported higher prevalence among lower socioeconomic group. Palaniappan P et al [19] reported around 40-86.3% of ADHD presented with comorbidities, similar to our study (60.42%). The comorbidities associated were identified as reading difficulty (13.5%), writing difficulty (10.4%), behavioural difficulties (11.45%), poor social behaviour (17.7%), poor academic performance (18.75%) and conduct disorders (2.08%).
Recognition of these associated comorbid conditions carries important implications for assessment, treatment approaches and prognosis. Poor outcome is expected in a child with associated adverse psychosocial circumstances and comorbities [20]. Pharmacological, behavioural and combined pharmacological and behavioural interventions are the best commonly prescribed treatments for ADHD.

Recommendations
It is a multidisciplinary approach which includes parents, teachers, paediatricians, ophthalmologist and psychologist.
1) School Health Services: Awareness program regarding ADHD to be included in the school health program for screening ADHD and also to sensitise the class teacher to identify children and refer to paediatrician for further evaluation, so to give guidance and counselling to parent and child.
2) To identify the comorbid conditions like reading difficulty, writing difficulty etc and give special education to these children at school & home. So that to improve the academic performance and decrease the incidence of school drop outs.

Conclusion
From the results of the present study it can be concluded that 1. The prevalence of ADHD among urban Government primary school children in Chennai, TAMILNADU is 9.67% 2. Children from lower socioeconomic status are more vulnerable for ADHD in our study but requires study among population representing all socioeconomic strata.
3. Poor academic performance was the most common associated comorbid condition, followed by poor social behaviour.