The symptoms of ADHD are often embedded within a range of other developmental and behavioural concerns. This study examined the factors that differentiate children with ADHD from those without in a group of children referred with similar presenting symptoms. The primary objective was to identify factors associated with a positive ADHD diagnosis in children presenting with common symptomatology. A secondary objective was to determine the prevalence of comorbidity in children with and without ADHD.
Children (aged 4–9 years) referred to the ADHD Assessment Clinic in Melbourne between 2004 and 2014 were assessed as follows:
- Prior to the clinic appointment, parents and teachers completed a questionnaire aimed at gathering demographic information and evaluating the social and academic functioning of children
- At the clinic, parents were interviewed by the paediatrician, and the child was subjected to psychological and special education assessments
- Case conference, where all of the information was presented and discussed to formulate the child’s primary and secondary problems and degree of impairment, and to generate a prioritised list of recommended interventions.
Of the 190 children assessed, 69.5% (n=132) were diagnosed with ADHD: 87% combined type; 8% predominantly inattentive type; 5% predominantly hyperactive/impulsive type.
In the univariable analysis (n=190), the factors associated with an increased probability of a positive ADHD diagnosis were: male gender (odds ratio [OR]=2.24, p=0.04), ADHD symptom severity by both parent (OR=1.53, p=0.01) and teacher report (OR=3.96, p<0.001), presence of an externalising disorder (OR=2.75, p=0.002), impact of emotional/behavioural problems by both parent (OR=1.54, p=0.009) and teacher report (OR=2.46, p<0.001), teacher-reported peer problems (OR=1.59, p=0.01) and teacher-reported learning difficulties (OR=2.39, p<0.001). In the multivariable analysis (n=126), teacher-reported ADHD symptom severity (OR=3.38; p=0.001) and teacher-reported learning difficulties (OR=1.91; p=0.03) were associated with an increased odds of a positive ADHD diagnosis.
Among children diagnosed with ADHD, the proportions of those with one comorbidity or with more than one comorbidity were 39% and 37%, respectively. Among children without an ADHD diagnosis, 40% had no other diagnosis, 41% had one diagnosis and 19% had more than one diagnosis. In both groups, oppositional defiant disorder (ODD), anxiety disorder, learning disability and language disorder were the most prevalent other diagnoses. Except for ODD, which was more common in children with ADHD than in those without (51% versus 31%, p=0.005), there were no significant differences in the prevalence of the other diagnoses between the two groups.
The findings underscore the importance of teachers’ reports in aiding the diagnostic process of ADHD, and also highlight the importance of evaluation for comorbid disorders regardless of the primary diagnosis.
Efron D, Bryson H, Lycett K, et al. Children referred for evaluation for ADHD: comorbidity profiles and characteristics associated with a positive diagnosis. Child Care Health Dev 2016; 42: 718-724.