Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that causes a 25-30 percent delay in the development of the neural pathways in the brain that control executive function skills. In other words, a 10-year-old boy with ADHD may exhibit behaviors (such as difficulty sitting still or being impulsive) that are more typical of a 7-year-old, or a 16-year-old girl may have the organizational skills of a 12-year-old.

Contrary to its name, ADHD is not a deficit in being able to pay attention. It is a deficit in being able to regulate attention, which results in periods of intense focus (i.e., “hyperfocus”) and poor focus.

The presentation of ADHD changes as a child develops. The hyperactivity and impulsivity that is more obvious during childhood become less evident, and the difficulties with attention regulation become more prominent during the teen years, particularly as school becomes more difficult. By adulthood, most people with ADHD have developed compensatory strategies to cope with their symptoms, but they still may struggle with procrastination, disorganization, and difficulty completing effortful tasks.