ADHD, also known as Attention Deficit Hyperactivity Disorder, is a condition where an individual has attention difficulty, hyperactivity, and impulsiveness. To answer your question, ADHD affects someone at school because that individual will have no concentration and focus on his or her schoolwork. Someone with ADHD wants to find something to stimulate themselves. They want to find something really interesting. Most likely, an individual with ADHD would be doing something that he or she is not supposed to do in the classroom. ADHD subsides over time in many of the mild cases, but in some of the more severe cases, it may last for the rest of his or her life. ADHD in an individual can lead to troubled relationships, low self-esteem, difficulty in school, and many more. Anyways, ADHD affects someone at school because of their difficulty concentrating and focusing with attention. Hope this helped find the answer that you were looking for. Good day to you.