The Genetic and Environmental Contributions to Attention Deficit Hyperactivity Disorder as Measured by the Conners’ Rating Scales—Revised

The majority of published reports on twin studies of attention deficit hyperactivity disorder (ADHD) have indicated robust additive genetic influences and unique environmental influences. These studies typically used DSM ADHD symptoms collected by telephone or interviews with mothers. The purpose of this study was to test the genetic architecture of ADHD by using the ADHD index from Conners' Rating Scales-Revised.