For so many years, ADHD was thought to be something only young boys had. Bad behavior in the classroom, impulsivity, hyperactivity, or bad grades were thought to be the only signs. At one point it was actually called a behavior disorder. Behavior is more like a response to some of the symptoms, and it really is all about the brain. Generally, there are differences between boys and girls with ADHD. So understanding girls with ADHD can present differently is important. Once you understand the differences, you will be able to help your daughter if she has been diagnosed with ADHD, or if you are suspicious she might have it.