Although symptoms tend to be different in children and adults, ADHD appears to be caused by the same neurochemical disturbances.

Even when diagnosing adults, clinicians must consider symptoms that do not apply, such as “often leaves seat in classroom,” Faraone says. “Developmentally sensitive criteria may be needed to fully capture the range of adult ADHD in the population,” he says. Clues in the Brain Although symptoms tend to be different in children and adults, ADHD appears to be caused by the same neurochemical disturbances. For example, neuro­imaging studies of both children and adults have found decreased availability of the neurotransmitter dopamine inside a part of the brain called the striatum. Recent studies suggest other important brain differences in both children and adults. For example, George Bush, an assistant professor of psychiatry at Harvard Medical School, and colleagues have a paper in press that shows that a part of the brain called the anterior cingulate cortex (ACC) is approximately 13 percent smaller in people with ADHD. In a separate study currently being reviewed, the same researchers found that cortical (gray matter) thickness is significantly less in the “attention network” (ACC, dorsolateral prefrontal cortex, and parietal cortex) of unmedicated adults with ADHD, compared to matched controls. Despite the fact that neuroimaging studies consistently show that people with ADHD have certain unique variations in brain structure and function, neuroimaging cannot yet be used to diagnose ADHD, Bush cautions. But that may change in the not-too-distant future. Developing an objective test for ADHD could be a very important step that might help millions of children and adults be properly diagnosed—and obtain appropriate treatment—for this “distinct and truly disabling disorder,” Bush says.  Even when diagnosing adults, clinicians must consider symptoms that do not apply, such as “often leaves seat in classroom,” Faraone says. “Developmentally sensitive criteria may be needed to fully capture the range of adult ADHD in the population,” he says. Clues in the Brain Although symptoms tend to be different in children and adults, ADHD appears to be caused by the same neurochemical disturbances. For example, neuro­imaging studies of both children and adults have found decreased availability of the neurotransmitter dopamine inside a part of the brain called the striatum. Recent studies suggest other important brain differences in both children and adults. For example, George Bush, an assistant professor of psychiatry at Harvard Medical School, and colleagues have a paper in press that shows that a part of the brain called the anterior cingulate cortex (ACC) is approximately 13 percent smaller in people with ADHD. In a separate study currently being reviewed, the same researchers found that cortical (gray matter) thickness is significantly less in the “attention network” (ACC, dorsolateral prefrontal cortex, and parietal cortex) of unmedicated adults with ADHD, compared to matched controls. Despite the fact that neuroimaging studies consistently show that people with ADHD have certain unique variations in brain structure and function, neuroimaging cannot yet be used to diagnose ADHD, Bush cautions. But that may change in the not-too-distant future. Developing an objective test for ADHD could be a very important step that might help millions of children and adults be properly diagnosed—and obtain appropriate treatment—for this “distinct and truly disabling disorder,” Bush says. 

ADHD, adult, brain, cortex, prefrontal, pfc, neurotransmitter, dopamine, neuroimaging, imaging, striatum