Doctors and parents have long been left to guess at which children with a diagnosis of attention-deficit hyperactivity disorder, or ADHD, will go on to become adults with significant attention problems, how well they will navigate the challenges of adulthood and whether early recognition of -- and medication for -- their condition will make any difference in the trajectory of their lives.
Now a series of studies following 457 Finnish children from birth to ages 16 to 18 offers a glimpse of how the primary symptoms of ADHD typically evolve. At the same time, the studies raise provocative questions about the long-term effect of treating those symptoms with medication.
The studies focus on a subset of 188 Finnish teens considered to have "probable or definite ADHD" that will follow them into adulthood and 103 kids with conduct disorder -- behavior issues that fall short of an ADHD diagnosis but put kids at higher risk for similar problems. Those teens were compared with a group of Finnish teens with no ADHD diagnosis.
Researchers found it is the can't-sit-still kids -- the stereotype of the "ADHD generation" -- who are most likely to mature out of the disease. Among those with persistent ADHD, they also found, half have problems with cognitive skills that are key to success in adulthood, but half have no such deficits.
And when researchers compare the findings from Finland to studies of Americans with ADHD, an even more intriguing discovery emerges: By the time they're in their late teens, those who receive drugs for attention problems seem to fare about the same as those who do not.
That is sure to fuel a simmering debate over the extent to which American kids with ADHD receive medication, often with little other support. In Finland, medication for ADHD is extremely rare.
"This begs the question: Are current treatments really leading to improved outcome over time?' " wrote UCLA neuropsychologist Susan L. Smalley and co-author Dr. Marjo-Riitta Jarvelin in a special section of December's Journal of the American Academy of Child & Adolescent Psychiatry. Smalley co-directs UCLA's Center for Neurobehavioral Genetics. Jarvelin is a professor of public health and of medicine at Imperial College School of Medicine in London and University of Oulu, Finland, respectively.
UCLA neuroscientist Robert Bilder, who was not involved in the Finnish research, said the studies suggest that ADHD might best be treated, in some kids, by shoring up weaknesses in underlying cognitive skills rather than by focusing exclusively on behavioral symptoms that can change with age.
"We all hope in the future we'll find the optimal combination of treatments -- whether behavioral or pharmacological -- that'll provide young people with these problems the best chance to succeed in school and social environments," Bilder said. "It's clear so far that no treatment's been identified that's a panacea."
Two decades ago, as the diagnosis and medication of American children with ADHD began to soar, researchers and psychiatrists scarcely entertained the possibility of adults with ADHD. Today, experts estimate that 4.4% of American adults -- more than 10 million people -- suffer from attention problems serious enough to warrant a diagnosis of ADHD.
But like the generation of children first diagnosed in large numbers with ADHD, research on what the disorder looks like across the life span has just begun to mature.
Symptoms that persist
The new research suggests that, as children with ADHD grow into adolescence, it is the dreamy, forgetful, inattentive types who are most likely to continue to struggle with the disorder -- especially if they also suffered from depression, anxiety or serious behavior problems in their preteen years. When their childhood symptoms included hyperactivity and impulsiveness as well as inattentiveness, their chances of having adult ADHD grew higher still.
Underscoring the strong role of genes in the development of attention deficit disorders, the studies found that a child's likelihood of having ADHD that persists into adulthood is significantly greater if either parent -- but especially his or her father -- suffers from serious attention problems too.
By contrast, those whose childhood symptoms were confined to hyperactivity are the most likely to mature out of the disease in adolescence, the Finnish studies found. By age 18, most with persistent ADHD will struggle with mental rather than physical restlessness.
In all, roughly 2 in 3 of the Finnish children who were diagnosed with ADHD as children continued to exhibit severe attention problems between ages 16 and 18.