derstanding of the danger such objects pose for
Earth. Observations of surface conditions on Venus
and Mars helped to assess the unique conditions on
Earth for life compared to global warming on Venus
or global cooling on Mars. The uniqueness of Earth
was also evident from observations of the unusual
nature of giant extrasolar planets. The energy of the
universe was seen in a new light with the discoveries
of galactic black holes, gamma-ray bursts, and the ac-
celerating expansion of the universe.
Further Reading
Rees, Martin.Our Cosmic Habitat.Princeton, N.J.:
Princeton University Press, 2001. A popular ac-
count of the nature and expansion of the uni-
verse by the Astronomer Royal of Great Britain.
Seeds, Michael.Astronomy: The Solar System and Be-
yond.Belmont, Calif.: Wadsworth, 2006. A well-
illustrated textbook with a comprehensive cover-
age of astronomy.
Sobel, Dava.The Planets.New York: Viking Press,
- An engaging discussion of the planets and
recent planetary research.
Joseph L. Spradley
See also Hale-Bopp comet; Hubble Space Tele-
scope; Mars exploration; Science and technology;
Shoemaker-Levy 9 comet; Space exploration; Space
shuttle program.
Attention-deficit disorder
Definition Neurobehavioral developmental
disorder
The 1990’s saw a dramatic increase in the medicating of
children with attention-deficit disorder and a correspond-
ing nationwide controversy.
Often referred to as the disorder of the 1990’s, atten-
tion-deficit disorder (ADD) came to be the most
commonly diagnosed mental health condition in
American children during the decade. A neurobe-
havioral developmental disorder characterized by
inattentiveness and hyperactivity, the condition was
widely studied, debated, and diagnosed. One of the
earliest descriptions of the disorder comes from a se-
ries of lectures published in 1902 by George F. Still in
which Still described a group of children with impul-
sive characteristics that today would be associated
with ADD. The disorder was once called “morbid de-
fect of moral control,” “post-encephalitic behavior
disorder,” “minimal brain dysfunction,” and “hyper-
kinetic reaction of childhood.” It is more popularly
known as attention-deficit/hyperactivity disorder
(ADHD).
In 1994, diagnosticians distinguished between
two separate sets of symptoms: inattention and hy-
peractivity-impulsivity. While symptoms usually oc-
cur together, a diagnosis can nevertheless be made
when symptoms occur separately. The diagnosis usu-
ally transpires after a child enters school, when in-
creased focus on details concerning reading, writ-
ing, and socializing becomes necessary. Children
diagnosed with ADD have difficulty finishing school-
work or any task that requires protracted periods of
concentration. Fidgeting, squirming, uncontrolled
walking, running, and talking are also considered
symptomatic. ADD is said to affect 3 to 5 percent of
all children and remains more prevalent among
boys. Health professionals cannot determine any
root cause for the elusive condition.
During the 1990’s, which the President George
H. W. Bush and Congress declared the “Decade of
the Brain,” the use of psychostimulant medications,
including Ritalin (the most popular treatment),
Adderall, Concerta, and Metadate increased dra-
matically. Indeed, by 1996, ADD accounted for at
least 40 percent of all children’s references made to
psychiatrists. That same year, an article inForbesmag-
azine demonstrated that the rise of Ritalin consump-
tion had increased fourfold between 1989 and 1994.
These statistics prompted the U.S. Drug Enforce-
ment Administration (DEA) to report the rise of
psychostimulant medication use among children to
the United Nations International Narcotics Control
Board. Subsequently, the United Nations reported
that 10 to 12 percent of all male schoolchildren in
the United States were taking Ritalin. Across the
United States, children lined up in school hallways
for school nurses to hand out daily doses.Ritalin Controversy Although the American Medi-
cal Association (AMA) called ADD one of the best-
researched disorders in medicine, it became an in-
creasingly visible source of controversy during the
1990’s, coming under the scrutiny of the media, so-
cial groups, and churches. Throughout the decade,
magazine articles suggested that American children
were being overmedicated. The increasing numberThe Nineties in America Attention-deficit disorder 63