From the moment Julia entered first grade, she appeared to spend most of her time daydreaming. She needed more time to complete assignments than the other children did. As she moved through elementary school, her test scores deteriorated. She felt increasingly unable to do her homework or follow the teachers instructions in class. She made few real friends and said her teachers got on her nerves. She complained that her parents pressured her all day long and that nothing she did was right.
Julia was actually very friendly and talkative, but a lack of self-control made others feel uneasy around her. By age 14, she found that concentrating on assignments seemed impossible. She constantly lost her belongings. Neuropsychological exams showed Julia was of average intelligence but repeatedly interrupted the tests. She was easily distracted and seemed to expect failure in everything she did. So she just gave up. Ultimately Julia was diagnosed with attention-deficit hyperactivity disorder (ADHD) and was treated with methylphenidate, one of the standard drugs for her condition. The medication helped Julia organize her life and tackle her schoolwork more readily. She says she now feels better and is much more self-confident.
Julias symptoms constitute just one profile of a child with ADHD. Other girls and boys exhibit similar yet varied traits, and whereas medication has helped in many cases, for just as many it provides no relief. With the number of cases increasing every year, debate over basic questions has heightened: Is ADHD overdiagnosed? Do drugs offer better treatment than behavior modification? Recent progress in understanding how brain activity differs in ADHD children is suggesting answers.
What Causes ADHD?
ADHD is diagnosed in 2 to 5 percent of children between the ages of six and 16; approximately 80 percent are boys. The typical symptoms of distractibility, hyperactivity and agitation occur at all ages, even in adults who have the condition, but with considerable disparity. Children often seem forgetful or impatient, tend to disturb others and have a hard time observing limits. Poor impulse control manifests itself in rash decision making, silly antics and rapid mood swings. The child acts before thinking. And yet ADHD children often behave perfectly normally in new situations, particularly those of short duration that involve direct contact with individuals or are pleasurable or exciting, like watching TV or playing games.
Precursor behaviors such as a difficult temperament or sleep and appetite disorders have often been found in children younger than three who were later diagnosed with ADHD, but no definitive diagnosis can be made in those first three years. Physical restlessness often diminishes in teenagers, but attention failure continues and can often become associated with aggressive or antisocial behavior and emotional problems, as well as a tendency toward drug abuse. Symptoms persist into adulthood in 30 to 50 percent of cases.
Longitudinal epidemiological studies demonstrate that ADHD is no more common today than in the past. The apparent statistical rise in the number of cases may be explained by increased public awareness and improved diagnosis. The condition can now be reliably identified according to a set of characteristics that differentiate it from age-appropriate behavior. Nevertheless, debates about overdiagnosis, as well as preferred treatments, are sharper than ever.
Neurologists are making headway in informing these debates. For starters, researchers using state-of-the-art imaging techniques have found differences in several brain regions of ADHD and non-ADHD children of similar ages. On average, both the frontal lobe and the cerebellum are smaller in ADHD brains, as are the parietal and temporal lobes. ADHD seems to be the result of abnormal information processing in these brain regions, which are responsible for emotions and control over impulses and movements.