ADHD symptoms in children: ADHD (Attention Deficit Hyperactivity Disorder, ADHD) is a common neurobehavioral disorder, which mainly manifests symptoms such as inattention, excessive activity and impulsive behavior. So, what are the symptoms of ADHD in children? 1. Inattention. The most obvious symptom of ADHD in children is inattention, which manifests as poor attention stability, scattered attention, and difficulty in sustaining attention. Children may have trouble following instructions, be easily distracted when doing homework, forget details or routine