The comorbidity of ADHD in the general population of Swedish school-age children.
This study examined patterns of comorbid/associated diagnoses and associated problems in a population sample of children with and without DSM-III-R attention-deficit hyperactivity disorder (ADHD). Half (N = 409) of a mainstream school population of Swedish 7-year-olds were clinically examined, and parents and teachers were interviewed and completed questionnaires. The children were followed up 2-4 years later. Eighty-seven per cent of children meeting full criteria for ADHD (N = 15) had one or more and 67% at least two--comorbid diagnoses. The most common comorbidities were oppositional defiant disorder and developmental coordination disorder. Children with subthreshold ADHD (N = 42) also had very high rates of comorbid diagnoses (71% and 36%), whereas those without ADHD (N = 352) had much lower rates (17% and 3%). The rate of associated school adjustment, learning, and behaviour problems at follow-up was very high in the ADHD groups. We concluded that pure ADHD is rare even in a general population sample. Thus, studies reporting on ADHD cases without comorbidity probably refer to highly atypical samples. By and large, such studies cannot inform rational clinical decisions.
Kadesjö
B
B
Göteborg University, Sweden.
Gillberg
C
C
D000223:Adaptation, Psychological; D001289:Attention Deficit Disorder with Hyperactivity / Q000150:complications* / Q000523:psychology*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000209:etiology / Q000523:psychology*; D002648:Child; D015897:Comorbidity; D003430:Cross-Sectional Studies; D002658:Developmental Disabilities / Q000209:etiology / Q000523:psychology*; D005260:Female; D006801:Humans; D007859:Learning Disabilities; D008297:Male