Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood behavioral disorders. It is estimated that 10% of American school children are presently considered to have ADHD to some degree, an incidence that places it ahead of asthma and most infectious diseases. The problem can persist into adolescence and adulthood. It takes a great toll on children's abilities to learn effectively in school, and on their families' happiness.
For a condition so prevalent, surprisingly little is known about its causes. Imaging studies of children's brains have shown that areas involved in thinking, planning, and attention mature more slowly in those with ADHD compared to those without. Genetic investigations have suggested that certain small variations in several genes occur more commonly in ADHD, but no single genetic cause has been identified. Exposure in the womb to certain substances like alcohol can cause deficits in attention, and more such chemicals may be found in the future. Other disorders known to affect brain development and function, like certain types of epilepsy or Tourette syndrome, can be associated with attentional problems.
Since so little is known about the root causes of ADHD, no medical test can objectively identify the condition, the way that a throat culture can identify Strep throat. The diagnosis of ADHD is a clinical one. It is based on:
(1) Observations of the child's behavior in various settings by people close to him/her -- parents, teachers, coaches, etc. These may include standardized questionnaires, lists of problem behaviors which those familiar with the child can check off.
(2) Data on the child's academic functioning, such as grades, standardized test scores, and (most importantly) teachers' observations of his/her classroom function. The teacher often can comment (at least informally) about whether the child's difficulties could be due to a learning disability.
(3) A pediatric medical assessment to rule out conditions that can affect a child's learning and attention abilities, such as unsuspected hearing or visual deficits; subtle effects of illnesses such as asthma or allergies (as well as potential side effects of the medications used to treat them); or the presence of other behavioral conditions like Oppositional Defiant Disorder, Conduct Disorder, anxiety, and depression, which can co-exist with ADHD and which may require referral to a mental-health professional.
Once this information is collected, the findings are compared to the diagnostic standards for ADHD agreed upon by bodies such as the American Academy of Pediatrics, the American Academy of Child Psychiatry, and the National Institutes of Health. These are:
Inattention -- 6 or more symptoms for children up to age 16, or 5 or more for adolescents 17 and older and adults. Symptoms should have been present for at least 6 months, and are inappropriate for the person's developmental level:
In addition, the following conditions must be met:
If these diagnostic requirements are satisfied, a formal diagnosis of ADHD can be made. Based on the symptoms present, the diagnosis can one of three subtypes:
The procedure of ADHD diagnosis is subjective, and certainly can be imprecise. In addition, a child's functioning can change over time, so that he/she qualifies for different subtypes. Moreover, at least 50% of children who fall into the ADHD category as primary- or middle-schoolers may "outgrow" or mature out of the diagnosis by the time they reach high school or college. Nevertheless, the diagnostic procedure is worth carrying out. If ADHD is found, interventions -- both behavioral and medical -- can be started to help the child overcome his/her difficulties, and these can make school, family, and social life more rewarding.