1134
Chapter 31: Child Psychiatry
and concurrent attentional deficits are also more likely to show
aberrant frontal-striatal pathways on MRI than those patients
without attentional problems. MRI is also useful to elucidate
myelination patterns. MRI studies can also provide a baseline
for comparison of a later, potentially degenerative process in
the brain.
Hearing and Speech Evaluations
Hearing and speech should be evaluated routinely. Speech
development may be the most reliable criterion in investigating
intellectual disability. Various hearing impairments often occur
in persons who are intellectually disabled, but in some instances
hearing impairments can simulate intellectual disability. The
commonly used methods of hearing and speech evaluation,
however, require the patient’s cooperation and, thus, are often
unreliable in severely disabled persons.
Course and Prognosis
Although the underlying intellectual impairment does not
improve, in most cases of intellectual disability, level of adap-
tation increases with age and can be influenced positively by
an enriched and supportive environment. In general, persons
with mild and moderate mental intellectual disabilities have the
most flexibility in adapting to various environmental conditions.
Comorbid psychiatric disorders negatively impact overall prog-
nosis. When psychiatric disorders are superimposed on intel-
lectual disability, standard treatments for the comorbid mental
disorders are often beneficial; however, less robust responses
and increased vulnerability to side effects of psychopharmaco-
logic agents are often the case.
Differential Diagnosis
By definition, intellectual disability must begin before the age
of 18. In some cases, severe child maltreatment in the form
of neglect or abuse may contribute to delays in development,
which can appear to be intellectual disability. However these
damages are partially reversible when a corrective, enriched,
and stimulating environment is provided in early childhood.
Sensory disabilities, especially deafness and blindness, can be
mistaken for intellectual disability when a lack of awareness of
the sensory deficit leads to inappropriate testing. Expressive
and receptive speech disorders may give the impression of intel-
lectual disability in a child of average intelligence, and cere-
bral palsy may be mistaken for intellectual disability. Chronic,
debilitating medical diseases may depress and delay a child’s
functioning and achievement, despite normal intelligence. Sei-
zure disorders, especially those that are poorly controlled, may
contribute to persisting intellectual disability. Specific organic
syndromes leading to isolated handicaps such as failure to read
(alexia), failure to write (agraphia), or failure to communicate
(aphasia), may occur in a child of normal and even superior
intelligence. Children with learning disorders (which can coex-
ist with intellectual disability) experience a delay or failure of
development in a specific area, such as reading or mathematics,
but they develop normally in other areas. In contrast, children
with intellectual disability show general delays in most areas of
development.
Intellectual disability and autism spectrum disorder (ASD)
often coexist; 70 to 75 percent of those with ASD have an IQ
below 70. In addition, epidemiologic data indicate that ASD
occurs in approximately 19.8% of persons with intellectual dis-
ability. Children with ASD have relatively more severe impair-
ment in social relatedness and language than other children with
the same level of intellectual disability.
A child younger than the age of 18 years with significant
adaptive functional impairment, with an IQ less than 70, who
also meets diagnostic criteria for dementia, will receive both
a diagnosis of dementia and intellectual disability. However, a
child whose IQ drops below 70 after the age of 18 years with
newly acquired cognitive impairment will receive only the diag-
nosis of dementia.
Treatment
Interventions for children and adolescents with intellectual
disability are based on an assessment of social, educational,
psychiatric, and environmental needs. Intellectual disability
is associated with a variety of comorbid psychiatric disorders
that often require specific treatment, in addition to psychoso-
cial support. Of course, when preventive measures are available,
the optimal approach includes primary, secondary, and tertiary
interventions.
Primary Prevention
Primary prevention comprises actions taken to eliminate or
reduce the conditions that lead to development of intellectual
disability, as well as associated disorders. For example, screen-
ing babies for PKU, and administrating a low phenylalanine
diet when PKU is present, significantly alters the emergence
of intellectual disability in those affected children. Additional
primary prevention steps include education of the general pub-
lic about strategies to prevent intellectual disability, such as
abstinence from alcohol during pregnancy; continuing efforts
of health professionals to ensure and upgrade public health
policies; and legislation to provide optimal maternal and child
health care. Family and genetic counseling helps reduce the
incidence of intellectual disability in a family with a history of
a genetic disorder.
Secondary and Tertiary Prevention
Prompt attention to medical and psychiatric complications of
intellectual disability can diminish their course (secondary
prevention) and minimize the sequelae or consequent disabili-
ties (tertiary prevention). Hereditary metabolic and endocrine
disorders, such as PKU and hypothyroidism, can be treated
effectively in an early stage by dietary control or hormone
replacement therapy.
Educational Interventions.
Educational settings for chil-
dren with intellectual disability should include a comprehen-
sive program that addresses academics and training in adaptive
skills, social skills, and vocational skills. Particular attention
should focus on communication and efforts to improve the qual-
ity of life.
