percent of the variance in ADHD symptoms) and
neurobiological factors (with more support found for
irregularities in brain structures than for neuro-
chemical imbalances). The notion that sugar and
other dietary factors cause ADHD has received little
support. Family factors have not been found to play
a clear role in causing ADHD, although family influ-
ences are known to be important in the developmen-
tal course and emergence of associated symptoms.
The frequent co-occurrence of other conditions
and the extent to which ADHD symptoms cause prob-
lems in multiple settings (e.g. home, school) compli-
cate treatment of ADHD. These characteristics
contribute to the lack of consensus on the best treat-
ment for ADHD as well as the understanding that no
one approach works for all children and that many
children with ADHD will benefit from a multifaceted
treatment program. In addition, there is consensus
that treatments must be ongoing and must be sensi-
tive to children’s developmental level and other
strengths and needs of the child and the family. Stim-
ulant medications, the most frequently used treat-
ment, lead to dramatic improvements in symptoms in
about 80 percent of children with ADHD. To treat the
problems often associated with ADHD (e.g., conduct
problems, depression), which have not been found to
benefit from stimulant medications, parent manage-
ment training (PMT) is an effective approach. Al-
though there are many variations on PMT, standard
features typically include providing parents with an
understanding of the disorder and techniques for
managing their child’s behavior problems. Treat-
ment approaches that combine stimulant medication
with PMT have shown the greatest effectiveness. Al-
though many other interventions are available, the
evidence for their effectiveness is limited. At the be-
ginning of the twenty-first century, a large study fund-
ed by the National Institute of Mental Health was
underway and was evaluating the effectiveness of an
intensive intervention combining medication, PMT,
and classroom interventions. This study offered great
promise for providing information on the best treat-
ments for children with ADHD.
Conduct Problems (Disruptive Behavior)
The primary behaviors that fall into this category
are aggression, noncompliance, defiance, and aver-
sive interpersonal behavior. The DSM-IV categorizes
children with the less severe form of disruptive behav-
ior disorders as having oppositional defiant disorder
(ODD). Symptoms of ODD include a pattern of nega-
tivistic, defiant, noncompliant, and argumentative be-
havior, lasting for at least six months and causing
significant impairment in social or academic func-
tioning. In contrast, aggression and violation of rules
characterize conduct disorder (CD). The fifteen
symptom-based criteria are clustered into four
groups: (1) aggression to people and animals, (2) de-
struction of property, (3) deceitfulness or theft, and
(4) serious violation of rules. From the dimensional
perspective, ODD and CD are considered externaliz-
ing behavior problems, further distinguished as two
subtypes: delinquent and aggressive.
Estimates of the frequency of occurrence among
school-age children of ODD range from 5 percent to
25 percent and of CD from 5 percent to 20 percent.
As with ADHD, both ODD and CD are more frequent-
ly diagnosed in boys than in girls. ODD is twice as
common in males than females, although only before
puberty; rates are about even in postpubertal males
and females. The male to female ratio for CD is be-
tween two to one and three to one.
Children may be first diagnosed with ODD or CD
at any point in childhood. ODD may be present as
early as three years of age and is usually diagnosed by
the early school years. Some researchers consider
ODD to be a milder, earlier version of CD, although
the matter is controversial. Only about 25 percent of
children with ODD progress to the more severe CD.
On the other hand, most children who meet the
criteria for CD were previously diagnosed with ODD
and had persisting ODD symptoms. Children with
childhood-onset (i.e., before age ten years) of CD,
who are more likely to be boys, have been found to be
more likely to persist in antisocial behaviors over
time. In a 1996 research report, Terri Moffitt and her
colleagues delineated two alternative developmental
pathways for children with conduct problems. The re-
searchers described one group of these children,
those with early onset and problems that persist, as
following the life-course-persistent path, whereas
those whose conduct problems first emerged later in
adolescence and were typically limited to the teen
years were described as following the adolescent-
limited path.
The development of ODD or CD is likely to have
origins in multiple factors associated with diverse
pathways. Researchers have found evidence that sev-
eral factors are related to the development of ODD,
CD, or both: genetically based, early temperament
difficulties (e.g., having lower frustration tolerance),
neurobiological factors (e.g., low psychophysiological
arousal), social-cognitive factors (e.g., cognitive dis-
tortions), family patterns of interaction (e.g., inade-
quate monitoring of the child’s behavior), and family
environmental stress and adversity (e.g., marital dis-
cord).
Evidence for the effectiveness of treatment of
children with serious conduct problems is not promis-
ing. Although families are likely to be offered a range
of treatment options, none of them has been shown262 MENTAL DISORDERS