Browsing by Subject "relative age effect"

Aims of the study. Relative age refers to age differences between children in a school class or in another age-based group of children. In research conducted in the United States and Canada, relative age has been connected to the probability of being diagnosed with Attention Deficit Hyperactivity Disorder (ADHD). According to studies, children who are the youngest in their class have a higher probability of being diagnosed with ADHD. Researchers have hypothesized that this effect could be explained by teachers mistaking the immaturity of the youngest children for ADHD. Other possible mechanisms of the relative age effect include underdiagnosing the relatively older children in a class, and the classroom environment exacerbating ADHD symptoms in the relatively younger children. The aim of this study is to examine whether relative age has an influence on the prevalence of ADHD diagnoses among the patients of Finnish specialized medical care in Helsinki Metropolitan area. Methods. This study compared the birth date distributions of patients diagnosed with ADHD (the sample) and all those born in Helsinki within the same time period as the sample (1983-2011) with a x2 goodness-of-fit test. The sample (N=3051) consisted of patients from child psychiatric and child neurological specialized medical units at the Helsinki University Central Hospital (HUCH), including patients of outpatient clinics as well as of inpatient wards. The sample included all patients treated for ADHD at the aforementioned units between 2nd January 2000 and 2nd May 2013. During their treatment, patients were between 1 and 18 years of age. In total, 2596 of them were boys and 455 girls. The data was collected from hospital patient records. Results and conclusions. The birth date distribution of patients diagnosed with ADHD differed statistically significantly from the birth date distribution of all those born in Helsinki. Those born during the last quartile of the year, who are the youngest in their class in Finland, were 31 % more likely to enter HUCH specialized medical care as ADHD patients than those born in the first quartile. It is not known whether the effect of relative age was caused by a systematic error in recognizing or diagnosing ADHD patients, or whether being among the youngest in a class could increase ADHD symptoms in some children. Clarifying the influence mechanisms of the relative age effect requires further studies