A Concentration Killer: Study Shows Brain Chemistry Defect Is Key To Attention Deficit Hyperactivity Disorder In Adults:
"For the first time, research directly points to a dopamine production defect in adults with attention deficit hyperactivity disorder (ADHD). The brain chemical findings could lead to more effective treatments for these patients who are inattentive, impulsive, and hyperactive.
Previous evidence suggested that a dopamine malfunction occurs in those with ADHD. For example, drugs that enhance dopamine function appear to quell the disorder's symptoms. "Our finding, however, is the first direct evidence of a targeted dopamine deficit in adults with ADHD," says the study's lead author, Monique Ernst, MD, PhD, Senior Staff Fellow at the National Institutes of Health. "We found that the activity of an enzyme involved in the production of the chemical dopamine is lower than normal in a specific brain area."
In the study, the researchers analyzed the brains of 17 ADHD adults with positron emission tomography (PET). The PET images, which highlighted the activity of the dopamine-producing enzyme, DOPA decarboxylase, indicate that an abnormality in dopamine production occurs in only one of the dopamine-rich brain regions, the anterior frontal cortex. This region underlies motor activity and cognitive processes, including attention."