Childhood Development: ADHD and Problem Behavior

Two new studies were recently published that shed light on several aspects of childhood behavioral development. The first has to do with how the brains of children with Attention Deficit / Hyperactivity Disorder (ADHD) develop differently from those of normal children. The second study, entitled "School Readiness and Later Achievement," assessed the power of early childhood social and academic skills to predict later math and reading achievement. I choose to discuss both of these studies because they are related in that they both examine aspects of childhood behavior that is often deemed unacceptable and in need of treatment. In the former case of ADHD, this treatment is often pharmaceutical. I learned about this new research from an article in the New York Times entitled “Bad Behavior Does Not Doom Pupils, Studies Say.” Although I think this headline might be a little too optimistic, both studies should be at least slightly encouraging to parents.

The ADHD brain development study involved 446 children, half of whom had been diagnosed with ADHD. Each of the children’s brains was scanned using MRI two or more times at about three year intervals between their early preschool years and young adulthood. The researchers examined the images of the brains to ascertain the thickness of over 40,000 cortex sites. Childhood brain development follows a pattern first of cortex thickening and later thinning when unused neurons are pruned away. They found that half of the cortex sites gained peak thickness about three years later, at about 10.5 years of age in the group with ADHD versus 7.5 in the control group (see picture on left). Nevertheless, the brains of children in both groups followed the same general developmental pattern. The brain’s frontal cortex was one of the areas where the children with ADHD showed the most delay in development. This area is thought to be responsible for many behaviors that are disturbed in people with ADHD, such as controlling impulses, focusing attention, and organizing complex tasks. Notably, one area of the brain, the motor cortex, actually matured faster in the children with ADHD which may explain the fidgetiness and excessive movement that sometimes characterize the hyperactive form of the disorder.

The second study set out to analyze which characteristics of preschool children would best predict their “later teacher ratings and test scores of reading and math achievement.” Among the early traits of preschool students, they found that school-entry math skills best predicted later reading and math performance, followed by early language and reading skills, and then attention skills. The most surprising result of the study was that there was no correlation between early “problem behaviors and social skills” and later math and reading achievement (see image at right). According to the New York Times article, “educators and psychologists have long feared that children entering school with behavior problems were doomed to fall behind in the upper grades.” Fundamentally, what the study says is that children who enter school being good at math and reading tend to continue to be good at math and reading regardless of whether or not they have poor social skills or act out. Put this way, the result does not seem as surprising. However, the researchers did attempt to control for the preschoolers’ cognitive ability, although they admitted that “despite our ability to control for cognitive ability … and despite our controls for concurrent reading skills in all six studies, it remains possible that our surprisingly large school-entry math coefficients overstate causal impacts.” Simply stated, the correlation between early math performance and later math and reading performance may just be the result of smart children being more likely to have early math skills than their less intellectually gifted peers. Nonetheless, just because early behavior and social skills don’t correlate with later academic achievement doesn’t mean nothing should be done to correct problem behavior, as being able to do math is of little use if a person is unable to interact with others.

Both of these studies should at the very least offer comfort to parents that are worried that any psychological or behavior problems their young children may have now will have a detrimental effect on their children’s lives forever. The ADHD brain imaging study shows that the brains of children who are diagnosed with ADHD at a young age develop in essentially the same pattern as those of normal children just a little bit later. Although it’s too early to tell, perhaps this new information will ease the pressure on parents to medicate their young children for ADHD if in many cases the disorder will go away on its own with a little patience. ADHD such as methylphenidate and amphetamine can help in some cases, but they have also been known to have serious side effects such as appetite suppression which in turn may cause stunted growth in young children. As for the second study, while it is very limited in scope, it may reassure some parents dealing with unruly children that the unruly behavior is at least an isolated problem and most likely will not affect academic performance.