Prevalence and diagnostic stability of ADHD and ODD in Turkish children: a 4-year longitudinal study.

Background: This study was designed to assess the prevalence of Attention-Deficit/Hyperactivity Disorder (ADHD) and Oppositional Defiant Disorder (ODD) in a representative sample of second grade students from a country in a region where no previous rates are available (Turkey). The second aim is to evaluate the differences in ADHD and ODD prevalence rates among four different waves with one-year gap in reassessments.

Method: Sixteen schools were randomly selected and stratified according to socioeconomic classes.