Research into Childhood Brain Disorders Still in Its Infancy

by Aalok Mehta

October 27, 2008

Scientists are just beginning to get a handle on how to study, diagnose and treat childhood brain disorders such as autism, bipolar disorder and learning disabilities, two prominent researchers in the field said at a panel discussion Oct. 22.

Speaking at the Dana Center in Washington, D.C., Jerome Kagan and Martha Denckla also warned that despite the field’s relative infancy, the number of these diagnoses has shot upward in recent years, and some of the causes—such as overdiagnosis and increased expectations in schools—are particularly troubling.

For example, we should all be concerned about the rise in the diagnosis of bipolar disorder in children, said Kagan, an emeritus professor of psychology at Harvard University. “The symptoms in these children do not match the symptoms in adults—90 percent [of diagnosed children have symptoms that] resemble the symptoms of attention-deficit hyperactivity disorder.” Bipolar disorder, he added, is often treated with more-powerful and longer-lasting drugs than ADHD.

In addition, “we are creating more children with problems because we have, in our infinite arrogance, decided to ignore readiness” for many of the tasks children will face in school, said Denckla, a neurologist at the Johns Hopkins University School of Medicine and director of developmental cognitive neurology at the Kennedy Krieger Institute. “There has been an enormous increase in failure of reading because children are being asked to read a year before they used to be.”

She also cited cases of children who hated to write because they had been taught handwriting before the fine-movement muscles in their fingers fully developed, resulting in an awkward grip with their pencils propped up near the base of their thumbs. That grip can make writing literally painful for them.

Understanding the causes

Many psychologists and doctors make diagnoses too quickly, the researchers said.

Getting a diagnostic profile of children who are showing neurological symptoms, for instance, takes at least four hours and requires psychological questioning, physiological tests and family interviews, Denckla said. “It’s very extensive. Unfortunately, it’s not covered by insurance.”

As a result, many children are being treated “carelessly,” Kagan added—often doctors prescribe drugs reflexively, before considering other options.

A poor understanding of the underlying biology of these disorders also is a factor in misdiagnosis, Kagan said. “Every one of these [childhood learning] disorders listed in [the Diagnostic and Statistical Manual of Mental Disorders] is heterogeneous both in cause and etiology,” he said. Many physicians diagnose patients by comparing their symptoms to those listed in the manual. But “the symptoms of autism alone likely have 18 to 20 different etiologies. It’s a terrible error to lump them all together and call them the autism spectrum” because treatments may differ depending on the cause, he said.

Researchers are only beginning to peel apart the various genetic, environmental and social factors that could be contributing to the so-called epidemic of diagnoses, Kagan said. They have yet to determine whether there has been a genuine rise in childhood disorders.

But already, research results suggest a large sociological role. “Because traits that cause distress or maladaptation change with history, it also follows that prevalence will change with history,” he said. For example, social phobias were not an issue before the rise of dense city and suburban living spaces, he said.

“No gene has accounted for more than 5 percent of the variation” in childhood mental illnesses, he added. In some cases, “class accounts for 30 percent.”

Learning from their subjects

As their understanding grows, scientists are coming up with more useful treatments, Denkla said. Drug therapies for ADHD seem particularly effective, for example, and appear to help damaged brains become more normal. Behavioral modification using positive reinforcement also works well in many cases, she said.

Things were different when she first started studying reading difficulties some four decades ago, she said. In her first experiment, she quickly learned how little she knew when one of her child test subjects said, “This is a stupid experiment,” and “I’ll tell you what the problem is.” He was having difficulty with names, she said, which showed her the importance of executive function in these disorders.

Now, she said, the research has led her and others away from a “what’s wrong model” and toward seeing disorders as conditions with strengths and weaknesses.

“It doesn’t mean we shouldn’t worry about them,” she said, because these disorders “can have enormous consequences.” But it does offer alternative methods of treatment and better ways to diagnose children who might be compensating for their difficulties.

In the end, both scientists repeated that much more research is necessary before doctors—and concerned parents—will have the answers they want.

“There is no secret,” Kagan said. “We’re still at the ground floor.”