The aim of this nationwide, cross-sectional study was to determine the prevalence and comorbidities of ADHD in children in a representative Turkish population.
The target population was 2nd, 3rd or 4th Grade students in urban schools assigned to study centres, which represented approximately 71.4% of the Turkish population. Using the Kiddie Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime version (K-SADS-PL), parents provided information to evaluate present and lifetime psychopathology. Parents and teachers completed the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV)-based screening scale for disruptive behaviour disorders in children and adolescents, which evaluates ADHD, oppositional defiant disorder and conduct disorder. Parents were also asked about the child’s relationship with siblings, relationships with friends, ability to do homework and general adjustment at home. Teachers were asked if the child was problematic and their general success in different areas of functioning, relationships with friends and self-esteem. Sociodemographic data were also collected.
Of the 5842 participants evaluated in this study, the overall prevalence of childhood ADHD was 19.5% when impairment was not considered. In terms of ADHD presentation, 11.0% had predominately inattentive type, 1.3% had predominantly hyperactive type and 7.2% had combined type. When impairment was considered, the overall prevalence of ADHD was 12.4%, with 6.8% presenting with predominantly inattentive type, 0.7% with predominantly hyperactive type and 4.9% with combined type. Regardless of presentation type, ADHD was significantly more common in boys than girls (p<0.001). For both parent and teacher ratings, DSM-IV-TR results were significantly higher for all subscales (attention-deficit; hyperactivity; oppositional-defiant; conduct disorder) among children with ADHD versus those without ADHD, regardless of impairment (p<0.001 for all domains).
The most common psychiatric comorbidities in children with ADHD included oppositional defiant disorder (15.1%), nocturnal enuresis (11.3%), simple phobia (7.8%), separation anxiety (6.1%), tic disorders (5.2%), social anxiety (3.2%) and major depressive disorder (3.2%). ADHD was significantly associated with depressive disorders, specific learning difficulty, oppositional defiant disorder, conduct disorder, intellectual disability (p<0.01 for all), nocturnal enuresis (p=0.02) and articulation disorder (p=0.033). Psychiatric comorbidities of both oppositional defiant disorder (p=0.002) and conduct disorder (p= 0.09) were observed more commonly in children with ADHD with impairment compared with those without impairment.
Potential limitations of this study are that it included only children in urban areas served by the study centres, so children in rural areas were not evaluated. Also, household sampling was not performed; therefore, other children not attending the enrolled school grades were not included.
The results from this study indicate that the prevalence of ADHD in children in Turkey is 19.5% without impairment and 12.4% with impairment. According to the authors, even if impairment is not described in children with ADHD, psychiatric comorbidities can still accompany the diagnosis of ADHD which may lead to impairment in the future.
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Ercan ES, Unsel-Bolat G, Tufan AE, et al. Effect of impairment on the prevalence and comorbidities of attention deficit hyperactivity disorder in a national survey: nation-wide prevalence and comorbidities of ADHD. J Atten Disord 2021; Epub ahead of print.