Method: A population of 187 children and adolescents was referred to an outpatient clinic for Child and Adolescent Mental Health in Norway regarding attention deficit hyperactivity disorder (ADHD). Examinations of the population were done using interviews and questionnaires with parents, teachers, children and adolescents regarding ADHD. After a review of all the assessments, the children and adolescents were classified as ADHD (96) and non-ADHD (91). In addition, when available, cognitive performance was registered.
Results: Seventy-one (74%) children and adolescents met the criteria for combined type ADHD (ADHD-C, both inattention and hyperactivity-impulsivity symptoms) and 21 (22%) predominantly hyperactive-impulsive type ADHD (ADHD-HI, hyperactivity-impulsivity). Referral age was from 6 to 18 years; 82% were boys. Nearly all of the ADHD group (93%) had comorbid conditions compared to half of the non-ADHD group (OR: 14; 95% CI 5.6 to 36, p=0.001). Disruptive behavior disorder, anxiety/stress related disorder and encopresis/enuresis were the main disorders. One out of three ADHD children had a low IQ, almost double as many as in the non-ADHD group (OR: 1, 5; 95% CI 0.5 to 3.9, p=0.5). Social dysfunctions were found in four out of five ADHD children. In an explorative binary logistic regression analysis with social dysfunction as the dependent variable and IQ, gender and ADHD/non-ADHD group as independent variables, a low IQ was the only predictable factor contributing to social dysfunction.
Conclusions: The study provides evidence for ADHD children and adolescents with combined ADHD type (predominantly hyperactivity and impulsivity) associated with comorbid conditions being relevant to low cognitive performance and low social skills.
Trial registration: Current Controlled Trials NCT01252446.