Attention Deficit/Hyperactivity Disorder (ADHD): age related change of completion time and error rates of Stroop test.

BACKGROUND Attention Deficit/Hyperactivity Disorder (ADHD) is a common neurobehavioral problem in children throughout the world. The Stroop test has been widely used for the evaluation of ADHD symptoms. However, the age-related change of the Stroop test results has not been fully clarified until now. METHODS Sixty-five ADHD and 70 age-matched control children aged 6-13 years were enrolled in this study. ADHD was diagnosed based on DSM-IV criteria. We examined the completion time and error rates of the Congruent Stroop test (CST) and Incongruent Stroop test (IST) in ADHD and control children. RESULTS No significant difference was observed in the completion time for CST or IST between the ADHD and control children at 6-9 years old. However, ADHD children at 10-13 years old showed significantly delayed completion time for the CST and IST compared with controls of the same age. As for the error rates of the CST and IST, ADHD and control children at 6-9 years old showed no difference. However, error rates of CST and IST in the ADHD children at 10-13 years were significantly higher than those of control of the same age. CONCLUSIONS Age may influence the results of Stroop test in ADHD children. For the ages of 10-13 years old, the Stroop test clearly separates ADHD children from control children, suggesting that it may be a useful screening tool for ADHD among preadolescent children.