626 CHAPTER 14
not affect children and their families as much, although they still cause signifi cant
distress and/or impair functioning: learning disorders and disorders of disruptive
behavior and attention. In the fi nal section, we examine briefl y other disorders of
childhood, which have symptoms that can overlap with those of other psychologi-
cal disorders or problems.
Some of the disorders discussed in this chapter are lifetime diagnoses. Individu-
als and their family members can become adept at managing, compensating for, and
working around the symptoms of these disorders. Neurological factors are often the
most direct cause of many of the disorders discussed in this chapter, such as mental
retardation and learning disorders; psychological and social factors may play a role,
but often only an indirect one. For instance, poor pregnant mothers and children
raised in poverty (social factor) may be more likely to be exposed to substances
that cause certain types of mental retardation in children. Psychological and social
factors also play a role in how well an individual adapts to and compensates for his
or her disorder.
For many of the disorders in this chapter, the specifi c mechanisms of feedback
loops among the three factors are not as well documented as they are for disorders
discussed in most other chapters. For this reason, some of the sections that describe
the contributions of neurological, psychological, and social factors do not include
information on feedback loops among these factors.Mental Retardation
When either Lela or Carlos calls Richie’s name, he often seems to ignore it. They
can tell that he’s not deaf—he clearly notices street noises and other sounds and he
startles in response to loud noises. He seems to understand someof what people
say to him, but his cognitive abilities are less developed than Javier’s and Pia’s were
when they were his age; Richie’s intellectual functioning defi nitely doesn’t seem
normal. Could he be mentally retarded?
In this section we examine mental retardation in more detail—its
criteria and causes and the treatments provided to people with this
disorder.What Is Mental Retardation?
Mental retardation refers to intelligence that is significantly below
normal—an IQ approximately equal to or less than 70 (where the mean
IQ is set at 100)—and that impairs daily functioning. The defi cits in in-
tellectual ability and daily functioning (see Table 14.1) must have begun
before 18 years of age, and thus cannot be the result of brain trauma in
adulthood. The IQ cutoff of 70 or less is two standard deviations or more
below average ability. Mental retardation, along with personality disor-
ders, is an Axis II diagnosis because the authors of DSM-IV wanted to en-
sure that symptoms of Axis I disorders do not overshadow the possibility
that a given individual has comorbid mental retardation (or a personality
disorder) (American Psychiatric Association, 2000). The term intellectual
disability is sometimes used as a synonym for mental retardation.
DSM-IV-TR specifi es the following four levels of mental retardation,
which are set by ranges of IQ scores (Criterion A). In general, the lower
the IQ score, the more impaired the individual is likely to be. However,
an individual’s IQ scores can vary by about 5 points because of testing
error, so the ranges generally allow a 5-point leeway for assigning the
level of retardation and level of adaptive functioning:- Mild mental retardation. The IQ score can range from 50–55 to 70; 85%
of people with mental retardation fall into this group. People in this mild
Table 14.1 • DSM-IV-TR Diagnostic Criteria
for Mental RetardationA. Signifi cantly subaverage intellectual functioning: an IQ of
approximately 70 or below on an individually administered IQ
test (for infants, a clinical judgment of signifi cantly subaverage
intellectual functioning).B. Concurrent defi cits or impairments in present adaptive
functioning (i.e., the person’s effectiveness in meeting the
standards expected for his or her age by his or her cultural
group) in at least two of the following areas:
communication,
self-care,
home living,
social/interpersonal skills,
use of community resources,
self-direction,
functional academic skills,
work,
leisure,
health, and
safety.C. The onset is before age 18 years.Source: Reprinted with permission from the Diagnostic and Statistical Manual
of Mental Disorders, Text Revision, Fourth Edition, (Copyright 2000) American
Psychiatric Association.Mental retardation
Intelligence that is signifi cantly below
normal—an IQ approximately equal to or
less than 70 (where the mean IQ is set at
100)—and that impairs daily functioning; also
referred to as intellectual disability.