Kids suffering from attention deficit hyperactivity disorder (ADHD) may have altered brain chemistry that prevents them from experiencing motivation and rewards like other people, according to a new study published in the Journal of the American Medical Association. Lead researcher Nora Volkow suggests that faulty transmission of the brain chemical dopamine
may be to blame for the difficulty people with ADHD experience trying to finish tasks that have no immediate payoff — the difference between doing homework, for instance, and playing a video game [CBC News].
The researchers used PET brain scans to determine how the brains of people with and without ADHD handled the neurotransmitter dopamine, a versatile chemical that is involved in regulating mood, attention, and learning.
In particular they measured levels of two proteins - dopamine receptors and transporters - without which dopamine cannot function effectively to influence mood. ADHD patients had lower levels of both proteins ...