Data from the NHIS indicate that: In 2001-2004, 7.7% of children ages 5-17 were reported to have been diagnosed with attention deficit hyperactivity disorder (ADHD).

Nine percent of White non-Hispanic children, 8% of Black non-Hispanic children, 2% of Asian non-Hispanic children, and 4% of Hispanic children were reported to have ADHD.

Almost 13% of White non-Hispanic children living in families with incomes below poverty level were reported to have ADHD -- the highest of any group.

Two to three times more boys than girls are diagnosed with ADHD (Pastor, p. 206).

Well-known researcher, Dr. Russell Barkley, has detailed the differences that can occur in reporting, due to the type of criteria used in any given report. Reported variations in the prevalence of ADHD may be due to differences in the ways samples are chosen, the criteria is used to define ADHD, and the age range and gender composition used during the sampling. For example, lower rates of ADHD are reported when the full DSM-IV criteria and parent reports are used and higher rates when teacher-only reports are used (Barkley, 2004)

One of the more reliable studies was conducted in 2005 by the U.S. Center for Disease Control (CDC). This survey looked at the number of children reported by their parents in 2003 to have or ever have been diagnosed with AD/HD. The CDC found that:

The prevalence of AD/HD was about 7.8% nationally but varied quite a bit across socio-economic groups and geographic location. The lowest incidence of 5% was reported in Colorado and the highest, of 11% was reported in Alabama. California, at 5.34% had one of the lowest reported incidences. This same report indicates that only about half of children of ages 4-17 years who were diagnosed with ADHD actually took medication for AD/HD. The highest prevalence for medication treatment was for children aged 9 to 12 years (CDC, p. 842).

Interestingly enough the prevalence of reported AD/HD symptoms increased with age, becoming highest for males aged 16 years and females aged 11 years and was lowest for preschool children. The highest rates were also noted among English-speaking, non-Hispanic, and insured children. In addition, the rates were most prevalent in families in which the most highly educated adult had a high school diploma and lower in those families in which the most educated adult had more or less education than a high school diploma. Families with incomes below the poverty line were also more likely to report a child with AD/HD (CDC, p. 844).

Although not a primary cause, "family environment adversity factors (eg. high degree of psychosocial stress, maternal mental disorder, paternal criminality, low socioeconomic status, foster care) have been linked to increased rates of ADHD" (Dopheide, p. 2)

Conclusion

ADHD is a disorder that affects 3% to 5% of school age children and may persist into adulthood. Evaluation by an experienced clinician who uses objective ratings from multiple informants in different settings is important for a reliable diagnosis. Once a diagnosis of ADHD is confirmed, a treatment plan can be developed which considers the existence of similar conditions. "Common comorbid conditions include oppositional-defiant disorder, major depression, anxiety disorders, learning disability, and Tourette's disorder. The presence of comorbid conditions can increase the likelihood of ADHD chronicity" (Plitzka, p. S50).

Several validated rating scales exist which are designed for optimal diagnostic assessment. A clinician with specialized expertise in child and adolescent neurodevelopment and behavior is able to generate a reliable diagnosis of ADHD. Because children are highly reactive to their environment:

It is crucial to enlist multiple informants such as parents, teachers, siblings, children, and caregivers and rate symptoms in multiple settings. A child must exhibit at least six out of the nine symptoms of inattention or...

The symptoms must present in multiple settings over a period of 6 months and have an onset by age 7 before a diagnosis is confirmed (Goldman, p. 111)
The incidence of ADHD will be examined from the years 1997 through 2007, with the aid of statistics from reliable sources and organizations who gather such numbers. It is evident, through a study of the literature available that accurate rates may not be had, though general increases will be reported, as they were between the years up to 1997. Whether these numbers reflect a growth in the number of school-aged children with ADHD, or a growth in the reporting of children who are believed to have ADHD may never be fully known, but most reliable sources that will be utilized have standard screening definitions, as noted above. In researching and studying the incidences that are noted, though they may vary from place to place, it may be determined whether the average number of school-aged children with ADHD has increased during the last decade.