ADHD and the Brain

Attention deficit hyperactivity disorder (ADHD) is a common behavioral disorder that emerges in children before the age of 7 and can extend into adulthood. It was discovered in 1902 and thought to be a symptom of brain damage.

The occurrence of ADHD is closely tied to biological factors such as the size and density of various brain structures and their chemical reactions.

Which part of the brain is different in children with ADHD and how is it different? Why might this play a role in ADHD symptoms? How is ADHD distributed across age and gender? How is ADHD treated?