According to the Centres for Disease Control, 6.1 million children have been diagnosed with some form of Attention Deficit Hyperactivity Disorder in the US. In the past research has suggested that ADHD and anxiety often go hand in hand. But studies have shown that children with anxiety don't necessarily have ADHD more often. Instead, these two conditions have symptoms that overlap — a lack of focus and inattention being two of them. Children with anxiety are often so caught up in their own thoughts that they do not pay attention to what is going on around them. This is especially troublesome at school where they are expected to pay attention to a teacher for hours at a time.