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Psychiatric-Mental Health Nursing

23.1 Intellectual Disabilities

Psychiatric-Mental Health Nursing23.1 Intellectual Disabilities

Learning Objectives

By the end of this section, you will be able to:

  • Explain the issues involved in diagnosing intellectual disabilities
  • Recall the major forms of intellectual disability
  • Outline approaches used in the treatment of intellectual disability

According to the American Psychiatric Association (2021b), intellectual disabilities affect 1 percent of the population. Most cases are found in males and, of all cases, about 85 percent of them are considered mild intellectual disability. The onset must be during the person’s developmental period, which is before they turn twenty-two (American Association on Intellectual and Developmental Disabilities, 2023). There are two areas of functioning involved in intellectual disabilities: intellectual functioning, the way a person learns and problem-solves; and adaptive functioning, a person’s ability to conduct their activities of daily living through communication and independent living.

Defining and Diagnosis of Intellectual Developmental Disorder

The preferred term for intellectual functioning that falls below an IQ of 70 and starts before age eighteen is intellectual developmental disorder, previously known as “mental retardation” (EPA, 2015). These disabilities can affect speech, thought, language, socialization, motor skills, and behavior (Empower Behavioral Health, 2023). Categories range from mild to severe. Classification is generally dependent upon the person’s IQ level in combination with their functioning. Levels and manifestations of intellectual disability vary greatly in children. Children with an intellectual disability might have a hard time communicating their needs, and an intellectual disability can cause them to develop more slowly than other children of the same age.

Causes of intellectual disabilities include genetic disorders (Down syndrome, Fragile X syndrome, Prader-Willi syndrome); maternal infections and exposure to alcohol during pregnancy; traumatic injuries during the birth process; and exposure to measles, whooping cough, or meningitis (EPA, 2015; Special Olympics, 2023). In 30 to 50 percent of cases, the cause is unknown; researchers suspect that in milder forms of intellectual disabilities with an unknown cause, environmental factors, such as lead, mercury, and polychlorinated biphenyls (PCB) exposure, may be determining factors (EPA, 2015). Intellectual disability can be caused by a problem that starts any time before birth to when a child turns eighteen years old.

Life expectancy for individuals with intellectual disability may be that of the general population, according to the Association on Aging with Developmental Disabilities (2024). Loved ones of those with intellectual disabilities are advised to plan for their support in later life, including care providers, housing, and possibly estate planning or assets held in trust (Helpers Community, 2022).

Diagnosis of intellectual developmental disorders typically occurs when a parent or medical provider notices that a child is not meeting age-appropriate developmental guidelines for speech, language, socialization, motor skills, and behavior (Empower Behavioral Health, 2023). The nurse or medical provider can assess the child’s development and then refer them for additional testing that might include a standardized IQ test (American Psychiatric Association, 2021a). The DSM-5 diagnostic criteria focus on three domains: conceptual, social, and practical. Diagnosis is no longer based solely on IQ test scores, but instead connects the severity of the impact the disability has on a child’s functioning to how they scored on an IQ test (American Psychiatric Association, 2013a). Therapies available include medication for specific symptoms, speech and behavior therapy, and counseling. Early intervention is important because it can improve the outcomes for the individual and their family.

The more severe the degree of intellectual disability, the earlier the signs can be noticed during developmental monitoring, such as the following (Centers for Disease Control and Prevention [CDC], 2021a):

  • sitting up, crawling, or walking later than other children
  • talking later than other children or having trouble speaking
  • difficulty remembering things
  • difficulty understanding social rules
  • difficulty seeing the results of their actions
  • difficulty solving problems

Refer children who are suspected to have an intellectual disability based on developmental screening to developmental pediatricians or other specialists for treatment. In children with a mild intellectual disability, there may not be an identification of deficit until after the child enters school, when they begin to show difficulties with learning (Committee to evaluate the supplemental security income disability program for children with mental disorders, 2015).

Conceptual Domain

The conceptual domain of adaptive functioning includes a person’s abilities in language, reading, writing, math, reasoning, knowledge, and memory (American Psychiatric Association, 2013a). Symptoms in this domain include slower learning; slower reading speed; difficulties with problem-solving, planning, and logical thinking; being easily distracted; and lacking focus (Cleveland Clinic, 2023a).

Social Domain

The social domain of adaptive functioning considers the individual’s ability to make friends and have relationships with others. It encompasses communication skills, empathy, and social judgment (American Psychiatric Association, 2013a). Symptoms in this area include the inability to understand social boundaries, difficulty understanding relationships with others—friendships, romantic relationships—and appropriate social interactions (Cleveland Clinic, 2023a).

Practical Domain

The practical domain of adaptive functioning considers the individual’s ability to act independently in their personal care, job role, school and work tasks, and money management (American Psychiatric Association, 2013a). Symptoms in this domain include having a slower ability to learn self-care activities, such as toileting, bathing, and dressing; inability to understand concepts, such as time or money management; and difficulty learning to complete chores (Cleveland Clinic, 2023a).

Types of Intellectual Disability

The types of intellectual disability are based on their causes, if known. Genetic mutations cause Down syndrome, fetal alcohol syndrome, Fragile X syndrome, and birth defects (Special Olympics, 2023). Cerebral palsy can be caused by trauma during delivery or infections during the pregnancy, such as toxoplasmosis or rubella, that interrupt fetal development (Cleveland Clinic, 2023a). Exposure to alcohol, tobacco, illicit drugs, medications, and radiation also interrupt fetal development. Certain medical conditions, such as hypothyroidism in the mother, can also affect the developing fetus and the intellectual abilities of the child once born. Head trauma to a baby or child can cause intellectual disabilities.

Cultural Context

Cultural Stigma toward Those with Intellectual and Developmental Disabilities (IDDs)

Individuals with IDD experience stigma. And stigma may vary by culture. Nurses should be aware of specific cultural stigmas that may be applied to this population of people in order to provide individualized treatment that aligns with personal/family beliefs. Some Asian and African cultures believe in interdependence and harmony, so they would be more apt to appreciate family interventions in which the person with IDD can feel accepted. In Thailand, for instance, it is important for families to be involved in cultural activities as a way of inclusion. Some Bangladeshi families want their family members who have IDD to be active participants in life, thus decreasing stigma. On the other hand, some Arab and Chinese families need more privacy because their cultures are more concerned with protecting the family from shame. These examples show the need for health-care providers to be cognizant that the interventions they provide must be culturally relevant in order to help decrease stigma while providing support to individuals and their families.

(Jansen-van Vuuren & Aldersey, 2020).

Down Syndrome

When a baby is born with an extra chromosome 21, they are diagnosed with Down syndrome. The medical term for having an extra chromosome is trisomy; therefore, the medical name for Down syndrome is Trisomy 21 (CDC, 2023a). Down syndrome is the most commonly diagnosed chromosomal disease in the United States and occurs in about one out of seven hundred babies born each year (CDC, 2023a).

According to the CDC (2023a), distinguishing physical factors for Down syndrome include:

  • a flattened face, especially the bridge of the nose
  • almond-shaped eyes that slant up
  • a short neck
  • small ears
  • a tongue that tends to stick out of the mouth
  • tiny white spots on the iris (colored part) of the eye
  • small hands and feet
  • a single line across the palm of the hand (palmar crease)
  • small pinky fingers that sometimes curve toward the thumb
  • poor muscle tone or loose joints
  • shorter in height as children and adults

Diagnosis typically happens during routine prenatal testing. There are two types of testing: screening tests, such as a blood test or ultrasound, and diagnostic tests, such as amniocentesis, that look at a sample of amniotic fluid. Screening tests are less invasive and considered safer for both the pregnant person and the fetus.

People with Down syndrome often have comorbidities, such as hearing loss, heart defects, and eye diseases. Medical treatments and surgery may be used to treat these conditions. Other services to help the person live a better life include speech, occupational, and physical therapy (CDC, 2023a). These services address the person’s functioning in the conceptual, social, and practical domains.

Fragile X Syndrome

Fragile X syndrome is a genetic disorder that involves the Fragile X Messenger Ribonucleoprotein 1 (FMR1) gene responsible for producing a protein that helps brain development. When a person has Fragile X, they do not have this protein, and that causes developmental delays—such as an inability to sit up, walk, or talk by developmental guidelines—learning disabilities, and behavioral problems—such as not making eye contact, hand flapping, or an inability to sit still (CDC, 2022a). If it is suspected that the child is not reaching developmental milestones due to this disorder, providers can perform genetic testing by collecting blood to test the person’s DNA (CDC, 2022a).

Physical features seen in a person with Fragile X include a long, narrow face, a large forehead and jaw, large ears and lazy eyes, soft skin, flat feet, decreased muscle tone, a high arch to the palate, and enlarged testicles in males (Cleveland Clinic, 2021). This disorder has no cure, but treatments include therapy to help a person learn to walk and talk. Medications may be used to help control behavior issues.

Early intervention services provided to children from birth to three years old help to increase the child’s development. Parents can access information about services that are available in their state by going to the Center for Parent Information and Resources website and clicking on the tab for their state.

Fetal Alcohol Syndrome

Fetal alcohol spectrum disorders (FASDs) can occur when a fetus is exposed to alcohol during the prenatal period (CDC, 2022b). The symptoms that individuals experience can range from mild to severe and affect physical, behavioral, and cognitive functioning. The most serious of the FASDs is fetal alcohol syndrome (FAS). Signs and symptoms of FAS include problems with the central nervous system, facial features (such as small eye opening, thin upper lip, low nasal bridge), and growth (such as a small head); learning disabilities; vision or hearing problems; and difficulty in school. While there are no specific tests to diagnose FAS, medical assessment includes the alcohol intake history during the pregnancy, the baby’s birth weight, facial features, and any problems with coordination or small head size. Although an exact number of cases is difficult to determine, the CDC has based an estimate on reviewing medical records and determined that in some areas of the United States one in one thousand live births is born with FAS (CDC, 2023b). According to the CDC (2022), there is no cure for FAS and treatment consists of medication management for some symptoms along with behavior therapy and parent training.

Prader-Willi Syndrome

Prader-Willi syndrome affects approximately one in 20,000 to 30,000 people in the United States (Fermin Gutierrez & Mendez, 2023). It entails an abnormality in the fifteenth chromosome that results in a genetic disorder affecting metabolism, behavior, and development. A hallmark symptom is a chronic feeling of not being full after eating (hyperphagia) combined with low metabolism that can lead to obesity (Cleveland Clinic, 2023b). Symptoms in infancy include a weak cry, weak muscle tone, lethargy, and inability to feed well. As the child grows, other physical symptoms may become more obvious. These include “almond shaped eyes, a long, narrow head, a triangular mouth, small hands and feet, short height, and underdeveloped genitals” (Cleveland Clinic, 2023b, para. 8). Behavioral and developmental symptoms, such as temper tantrums, intellectual disability, sleep problems, skin picking, and hyperphagia, also become more apparent. There is no cure for this syndrome and treatment is based on managing symptoms. Medications to increase certain hormones are given based on gender assigned at birth. Supportive therapies, such as physical, speech, and special education, can increase both physical and cognitive function in these children. Complications from the obesity related to overeating in Prader-Willi syndrome may include diabetes, heart disease and hypertension, respiratory problems, and sleep apnea (Cleveland Clinic, 2023b).

Treatment of Intellectual Disability

Treatment of intellectual disability is based on three categories: treatments or mitigation related to underlying causes, treatments of comorbid physical and mental disorders, and early behavioral and cognitive interventions (Committee to evaluate the supplemental security income disability program for children with mental disorders, 2015). All treatment should be person-centered and tailored to the individual.

Mitigation of Underlying Causes of Intellectual Disability

Research has shown that the causes of these disorders can be genetic, biological, psychological, and/or environmental (Committee to evaluate the supplemental security income disability program for children with mental disorders, 2015). While some of the causes occurring prenatally are related to genetics, and cannot be mitigated as easily, pregnant clients can have genetic testing and avoid other causes. Encourage clients to talk to their medical provider about genetic counseling prior to becoming pregnant if there is any family history of any genetic condition that can cause an intellectual disability. Educate pregnant clients to avoid things like drinking alcohol, smoking, and changing litter boxes (exposure to toxoplasmosis) during pregnancy. Keeping up with maternal vaccines that prevent illnesses prior to becoming pregnant, such as those for rubella, whooping cough, and meningitis, reduces the risk of fetal exposure. Accessing proper prenatal care and screenings can decrease the chances of premature birth. Although close observation by an obstetrician during the birth process can decrease brain injury that might occur during birth, there may still be birth complications that cause the baby not to get enough oxygen, resulting in an intellectual disability. After birth, parents can protect their children through proper use of car seats to prevent head trauma, by following the recommended vaccination and well-child appointments, eating a healthy diet, and limiting exposure to toxic metals, such as lead and mercury (Cleveland Clinic, 2023a).

Clinical Judgment Measurement Model

Take Action: Interventions to Prevent Cognitive Disabilities

A first-time mother is at her obstetrician’s office for her first prenatal visit. As part of the visit, the nurse goes into the exam room to provide education to the client. The nurse explains the importance of keeping up with her prenatal appointments and screenings. She also double-checks the client’s vaccination history to determine if any important vaccines are missing, explaining to the client that diseases, such as rubella, can cause future cognitive disabilities for her baby. The nurse confirms that the client has a cat at home and asks the client if there is someone else in the house who can clean the litter box because possible exposure to the toxoplasma parasite in the cat’s stool is harmful to the growing fetus (CDC, 2022c). As the client progresses through her prenatal visits, the nurse will continue to provide interventions to help ensure that the client is aware of prevention techniques to keep the baby safe from environmental factors that could cause cognitive disorders.

(Hooper, 2021; CDC, 2023b)

Treatment of Comorbid Physical and Mental Disorders

As many as 25 percent of people with intellectual disabilities have a psychiatric comorbidity. The most common of these are schizophrenia, depression, and attention-deficit hyperactivity disorder (Committee to evaluate the supplemental security income disability program for children with mental disorders, 2015). Medication and psychological support are the standard treatments. Genetically caused intellectual disabilities also may have associated physical disorders. Each of these is treated according to their severity—with medication or supportive therapies.

Early Behavioral and Cognitive Interventions

Under the Individuals with Disabilities Education Act (1990), early intervention services must be available to identify and help infants and toddlers (up to age three) who have disabilities (Center for Parent Information & Resources, 2017). Generally, early intervention programs, special education, vocational programs, day programs for adults, residential options, and case management (American Psychiatric Association, 2021a) may be available. The U.S. Department of Education and the Individuals with Disabilities Education Act (IDEA) offer special education programs for educational support once a child enters school. As a person ages, vocational training helps them learn how to work. An example of this is having a work partner to assist the high school individual in a work environment, such as a grocery store. Day programs provide the individual with an opportunity to get out of the house and be involved in activities with other people. There are residential options, such as group homes, for people whose intellectual disabilities are so severe that they are unable to care for themselves in their own home. Community agencies, such as local mental health centers, may also provide case management to assist clients with tasks, such as getting to medical appointments, managing medications, and grocery shopping.

More specifically, early intervention is a process that involves the child, the parent, and the intervention team meeting with the goal of providing problem-solving resources to the parent and child (Guralnick, 2017). The team develops an individualized education program (IEP) to address the child’s educational needs (Center for Parent Information & Resources, 2017). Another resource is services under Section 504 for accommodations in school, including extracurricular programs (PACER Center, 2018). Parents can find a list of early intervention programs, by state, on the Centers for Disease Control and Prevention website. These services can increase the child’s success in school by helping them overcome challenges they may have related to learning new skills (CDC, 2023c).


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