Theoretically, the earlier any disease is treated, the better, and the earlier the ADHD treatment for children is theoretically the better. However, the optimal time for medication is generally based on the appearance of clinical core symptoms in children after the appropriate time, that is, into the elementary school to the age of 6 years. Although the core symptoms of ADHD originate between the ages of 6 and 9 years, children often show preexisting symptoms of ADHD before the core symptoms appear, i.e., during the preschool years. For example, they may be excessively noisy and disruptive in some situations, they may also run around in class, be disobedient and feel obnoxious, and do things in a disorganized manner without any purpose. If any of these symptoms are present at an early stage, you should go to the hospital for a simple diagnostic evaluation. If there is a high risk of ADHD at that stage, intervention treatment can be given. Interventions are mainly attention training and behavioral interventions and do not require medication.