Anxious kids can present as being easily distracted, impulsive, angry, defiant when in reality they are anxious & may struggle in social situations. It is easily to confuse anxiety with disruptive behaviors including ADHD & oppositional & defiant behavior.. This article gives some good examples of how anxious behavior in kids can be misinterpreted in school.
https://childmind.org/article/how-anxiety-leads-to-disruptive-behavior/