Attention-deficit hyperactivity disorder (ADHD) in the early years: diagnostic issues and educational relevance.

In this study we discuss implications of the dimensional versus categorical approach in the diagnosis of attention-deficit hyperactivity disorder (ADHD) and focus on the educational relevance of an early assessment. In a longitudinal study in a German community sample we investigated the development of ADHD symptoms from kindergarten until the end of Grade 1 as well as the association to pre-academic skills and later academic performance. At three time points in kindergarten, children (original sample N = 793; Mn age 4 years 10 months) were assessed in regard to school-relevant precursors of reading, spelling and mathematical abilities; ADHD symptoms were rated by parents and preschool teachers. In elementary school academic performance in reading, spelling, and mathematics was measured with standardized tests. Results show that stability of ADHD symptoms during preschool was high considering the dimensional approach, whereas in regard to the categorical classification many children crossing the cut-off point at one measurement point did not do so at the next assessment. Furthermore, preschool ADHD symptoms were negatively correlated with all school-relevant precursors. This was more pronounced for symptoms of inattention than for hyperactivity/impulsivity. Observing later development, preschool ADHD symptoms predicted academic achievement in mathematics and reading at the end of Grade 1 even after individual differences in nonverbal intelligence and specific precursors had been statistically controlled for.