Turning ADHD on Its Head
"This study [looks at] very well-characterized kids with ADHD, not just with hyperactivity, but the whole spectrum of criteria for the diagnosis," says Wilens. "This is not generalizable to just active kids and should not be used as a reason to put someone on Ritalin [methylphenidate]."
Brown thinks that what confuses people is that many of the symptoms are problems everybody has sometimes. But those with the disorder experience the symptoms with greater frequency.
"So many times people will look at the list of symptoms and say, 'Well everyone has these,'" says Brown. "They don't realize that those with ADHD have chronic and severe difficulties that impair their ability to function."
Another watershed announcement came from a group at Massachusetts General Hospital in Boston. Researchers there found that there were measurable biochemical differences in the brains of adults with ADHD when compared with controls.
The researchers used Single Proton Emission Computed Tomography (SPECT) scans to look at a picture of the activity in a person's brain. In SPECT, a chemical is "labeled" using a very low level of radioactivity. When given to a patient, the areas of the brain that are using a labeled substance show up as areas that have more activity. What the researcher sees is the brain equivalent of a weather radar.
The researchers labeled the brain transmitter chemical dopamine, which is associated with movement, thought, motivation, and pleasure. They found that ADHD sufferers had 70% more dopamine transporters than the healthy controls. The scientists could not tell if that was a cause or an effect of the disorder.
To Wilens this builds on other studies showing similar distinctions in the brains of those with and without ADHD. He does note that the study only involved six patients, and it is preliminary in nature. He also pointed out that it shows that there is, indeed, an adult form of the disorder.
"One of the interesting things about this disorder is that there is good continuity between the childhood and adult forms of the disorder," says Wilens. "There is more and more evidence that ADHD in adults is a persistent form of the disorder."
Brown agrees, although he sees late recognition of the disorder as another consideration. What professionals are realizing now is that ADHD might not be recognizable in some cases until the child gets older and out of the more structured environments of grade school. Dealing with more complex tasks, different teachers, and moving from class to class may all combine to overwhelm those who had been doing well earlier.
The similarities between ADHD in adults and children in their symptoms and response to medications may help speed up investigation of treatment possibilities. Wilens notes that testing new medications on adults is easier and has less ethical baggage than testing them on children.