Introduction

Individuals of all ages with intellectual disabilities (ID) require both acute and long-term high-level services to treat their complex medical and psychiatric needs, and to minimize impacts of neuropsychiatric and medical comorbidity on their cognitive, health, and mobility limitations. Increasingly, the scientific evidence base is expanded by studies linking brain disorders to somatic disease states such as obesity, autoimmune disorders, and gut–brain influences.

In general, access to clinical care of all types for patients with ID remains limited by several critical factors (Kwok and Cheung, 2007), notably: (1) inadequate training of healthcare professionals, including psychiatrists (Marrus et al., 2013); (2) limited availability of appropriate and accessible transportation; (3) physical barriers to healthcare and exercise facilities to accommodate individuals with mobility issues; (4) high turnover rates of support staff, who also lack sufficient training; (5) the phenomenon known as diagnostic overshadowing (Reiss et al., 1982), which describes incorrect attribution of a treatable psychiatric illness to the underlying disability; and (6) under-recognition of, and failure to address, past trauma, disrupted attachments, and loss of identity, all of which contribute to ongoing psychiatric illness and behavioral challenges (Harvey, 2012).

Individuals with ID may lack abilities needed to make informed choices, and also basic autonomy over healthcare decision-making and medication use. An example is limitation in the ability to request a trial of tapering-off of medications causing adverse side effects or those prescribed for concurrent problems such as seasonal allergies, depression, or indigestion. The average number of physical and psychiatric diagnoses combined in individuals with ID is 10; likewise, the average number of medications received on a daily basis is 10. Emergency department use by individuals with disabling conditions accounts for a relatively high amount of expenditures (Rasch et al., 2013).

Vision and oral-health needs

In a study by Owens et al. (2006), only 28% of children with ID had normal vision compared to 75% of typically developing children. The authors found that refractive errors were the commonest cause of decreased vision, notably hyperopia, myopia, and astigmatism, and that 27–52% of persons with ID had a refractive error compared to 4–25% of the US general population. In addition, other vision problems, including strabismus, cataracts, and keratoconus, were more prevalent in the population with ID in comparison with the general population. Poor vision may account for repeated falling and also compounds intellectual and physical disabilities.

A study by Hulland and Sigal (2000) found that oral-health needs are also greater in persons with ID. The study showed that 18–84% of people with ID had untreated dental caries compared to 16–55% in the general population. Periodontal disease is common, and can produce fever, discomfort, and challenging behaviors, and is often missed in those with communication deficits (Prater and Zylstra, 2006). Oral bacteria also play a role in cardiac disease, which in turn also impacts brain health and function.

Deficiencies in oral healthcare behavior resulting in poor oral hygiene are common in persons with ID. Limited ability to understand the prophylactic importance of tooth brushing may be accompanied by poor physical coordination in persons with ID, both contributing to suboptimal oral hygiene. For outpatient dental appointments in uncooperative patients, the administration of a low dose of benzodiazepine, such as 1–2 mg of alprazolam an hour before appointments, may improve cooperation. In some cases, hospitalization may be necessary to perform dental care under anesthesia.

Healthcare screenings

Basic healthcare screenings such as mammograms and Pap smears occur at lower rates in individuals with developmental disabilities. Women with ID have higher risks for leukemia, and for other tumors including breast, uterine, and colorectal cancers (Rajan, 2013). Comorbidities render colonoscopy preparation and examination difficult; discussion of each patient’s individual issues prior to the event is needed. Only 19% of those with ID over age 50 years have had colorectal screenings (Fischer et al., 2012). Individuals with ID living with parents or independently are much less likely to have received preventive services than those in institutional community-based settings.

Cancer risks

Duff et al. (2001) found higher rates of gastrointestinal (GI) cancer in institutionalized persons with ID than in the general population, and also a significant number of deaths due to perforated stomach ulcers. They postulated that common Helicobacter pylori infections in institutionalized populations may account for this observation, and a different approach may be needed to eradicate this infection in persons with ID.

A population study conducted in Finland followed 2173 persons with ID from 1967 to 1997 for cancer incidence (Patja et al., 2001). The investigators found an increased risk of thyroid and gallbladder cancers, but a decreased risk of prostate, lung, and urinary tract cancers. The incidence of cancers overall was comparable to that in the general population. The reduced risk of lung cancer was likely explained by lower rates of smoking (9% versus 37% in the general population).

Although previous studies had reported up to a threefold increased rate of GI cancers in persons with ID, this study did not confirm an overall higher risk for GI cancers. However, there was increased risk identified for some cancer subtypes, notably of the gallbladder, esophagus, and undefined GI cancers. There is an increase in risk of esophageal cancers, correlated with an increased incidence of gastroesophageal reflux disease (GERD) and Barrett’s esophagus. The increase in gallbladder cancer rates may relate to the increased use of medications that affect hepatic enzyme function and also the increased overweight and fatty liver risk in persons with ID, as well as a higher incidence of gallstones.

Medical conditions impacting behavior/psychiatric illness with aging

Emotional supports normally protect against health problems, including heart disease and depression. However, individuals with ID have been shown to have significantly fewer emotional supports, as well as loss of key parental and grandparental supports with aging.

Individuals with long-term disabilities and especially immobility are more likely to experience early onset of obesity, coronary heart disease, diabetes, stroke, osteoporosis, arthritis, renal disease, various forms of cancer, infections, and injuries.

A Canadian study comparing the prevalence of chronic health conditions in people with and without ID found reported higher rates of thyroid disorder and heart disease than was reported in the general population (Morin et al., 2012). Food allergies, migraines, arthritis, and back pain were less likely to be reported in individuals with ID, although this finding could be explained partly by communication difficulties. Individuals with Down syndrome are also more prone to autoimmune diseases, including hypothyroidism, juvenile rheumatoid arthritis, and celiac disease, as well as blood dyscrasias.

Pain syndromes

Persons with ID often lack adequate pain treatment, and their pain prevalence is higher than in the general population (Baldridge and Andrasik, 2010). In the setting of cognitive and communication impairments in patients, healthcare professionals must employ a high index of suspicion and explore all possible sources of pain as contributors to observed challenging behaviors.

Menstrual cramps and discomfort can produce or worsen self-injurious behavior, aggression, or agitation (Carr et al., 2003). Hormonal interventions, for example the levonorgestrel intrauterine system (Mirena^®), may be employed to alleviate these problems (Pillal et al., 2010). Hormonal treatments may, however, also worsen moodiness and can cause deep vein thrombosis or strokes, especially if the dummy pills are skipped.

Approximately 70% of those with mobility problems associated with their disability are likely to have osteoporosis or osteopenia, which predisposes to hip, spine, and disk degeneration, and fractures. Individuals aging with cerebral palsy are more likely than the general population to suffer fractures (Murphy et al., 1995). Persons with ID and Down syndrome, hypogonadism, and those receiving antiepileptics or the ketogenic diet for seizure control are also at increased risk for osteoporosis.

Migraine or cluster headaches may be difficult to elicit in persons with ID owing to their impaired communication skills; sometimes they suffer rare but severe explosive outbursts accompanied by self-injury and aggression. Prophylactic treatments for headache may be helpful in such cases (Baldridge and Andrasik, 2010).

Neurological problems

Neurological conditions associated with ID and behavioral deterioration may include hyponatremia (related to medications or compulsive polydipsia), seizures, hydrocephalus, ventriculo-peritoneal shunt blockage, headaches, transient ischemic attacks, brain tumors, and encephalitis. These may present as acute, intermittent, or chronic mental status changes.

Antiseizure medications, including phenobarbital, phenytoin, mysoline, carbamazepine, and oxcarbazepine, may produce hyperactivity and behavioral worsening (Trimble and Cull, 1988). Topiramate may produce cognitive dulling, behavioral worsening, and renal calculi. Alzheimer’s disease has early onset in the late 30s in many adults with Down syndrome (Lott and Head, 2001).

Gastrointestinal problems

Gastrointestinal problems are common in ID, especially if autism spectrum disorders (ASD) and also present. Reflux esophagitis, reverse peristalsis, H. pylori infections, irritable bowel syndrome, fecal impaction, bloating, abdominal discomfort, nausea, constipation, and bowel obstruction may all present with behavioral problems, including self-injury. Pica (ingestion of non-food objects) may result in cessation of eating and drinking, for example if an object obstructs the esophagus.

Persons with ID and physical disabilities may suffer from swallowing difficulties, with associated choking, impaired hydration, and malnutrition (Kennedy et al., 1997). Aspiration may be silent, and lead to bronchitis, pneumonia, or even death, and requires that clinicians use a high index of suspicion when treating persons with ID and accompanying neurological disorders, including cerebral palsy (Chaney and Eyman, 2000).

Constipation and accompanying fecal impaction may produce associated unexplained behavioral changes, and are common in this patient population (Bohmer et al., 2001). Avoidance of white flour products and the simple dietary addition of pears and plums to replace apples and bananas may be helpful. Medical causes and medication side effects should also be considered.

Gastroesophageal reflux disease (GERD) may produce unexplained changes in behavior, and the individual with poor communication skills may be unable to communicate their discomfort. Cough, choking, and sore throat may be other associated signs of GERD, which also is common in individuals with Down syndrome (Bohmer et al., 2000).

Food allergies, including gluten and lactose intolerance, should be investigated if suspected. Liver disease, including hepatitis B infection, may account for sudden appetite and food preference changes. Celiac disease, an autoimmune disease produced by gluten antibodies and malabsorption of nutrients due to intestinal damage, may produce malaise, fatigue, anemia, hepatitis, arthritis, GI symptoms such as irritable bowel syndrome, peripheral neuropathy, and skin rash (Green and Jones, 2010). Psychiatric symptoms may include refusals related to the associated pervasive tiredness, as well as anxiety, panic disorder, depression, and psychosis (Carta et al., 2002; Genuis and Lobo, 2014). More studies are needed to clarify the relationship between gluten sensitivity, gluten intolerance, and ASD etiology or worsening.

Eating disorders

As defined by The International Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) (World Health Organization, 1992), eating disorders are diagnosed in 1–4% of young women in the general population. However, eating disorders are identified in 3–42% of persons with ID in institutions and 1–19% of those with ID in the community. Of persons with ID, 2–35% are obese and 5–43% are underweight (Gravestock, 2000).

Substance abuse

In mental health settings, substance-abusing persons with ID make up between 1% and 34% of the client population (Slayter, 2010). Persons with mild to moderate ID are more likely to develop substance abuse than those with more severe ID who have less independence in the community. There are risks of drug interactions and substance abuse in individuals with ID if they are receiving psychotropic medications. Clients with substance abuse in general are more likely to receive treatment, and also to remain in treatment, than are clients with substance abuse and ID. Substance-abuse treatment in persons with ID should highlight family education, applied behavior analysis, safety management, and social and communication skills development.

Sexuality and sexually transmitted diseases

Sexually transmitted diseases can occur in persons with ID, although they are commonly overlooked (Prater and Zylstra, 2006). Issues such as sexuality are underexplored in patients with ID in general.

Medication side effects

See also Chapter 13.

Drug interactions should be borne in mind when prescribing drug treatments and reviewing medication regimens. Medication side effects not already discussed may include allergy, skin rashes, and akathisia (motor restlessness). Lithium treatment in individuals with ID is more likely to produce disabling tremor, thirst and wetting, and toxicity, which goes undiagnosed longer and may be life-threatening. Several antiseizure agents induce hepatic enzymes to metabolize medications of multiple types, not only psychotropic medications, significantly more rapidly. These include phenobarbital, phenytoin, carbamazepine, and oxcarbazepine. Thus, the effective doses of other medications metabolized by the liver will be unknown, albeit lower. Conversely, the selective serotonin reuptake inhibitors (SSRIs) paroxetine, fluoxetine, and sertraline inhibit the liver enzyme cytochrome P450 2D6, thus raising effective doses of medications metabolized by that enzyme. For example, concomitant benzodiazepines may cause more sedation than expected, and atypical antipsychotics then produce even more excessive weight gain and associated morbidity and mortality.

Clinical approach

On an individual level, it is vital for clinicians to get to know each patient, and to ask detailed questions pertaining to medical and psychiatric illnesses, but also to explore details of his or her life on all levels. Viewing the person as a whole should also include questions regarding sleep, diet, exercise, and activities enjoyed, as well as family supports and pets. Individuals with hearing impairment may favor conducting interviews in written format over use of sign language, for example, if they can write. Engaging the person directly at their ability level with respect and adequate time empowers them to communicate directly regarding their problems, and to make better health choices. Many important details are elicited simply by chatting to the patient and their caregivers.

Spiritual beliefs and their impact on well-being and health should also be explored (Gaventa and Coulter, 2002; Peach, 2003). This may also be vital in serving other cultures; for example, certain African cultures’ beliefs that spirits of ancestors control one’s life, as well as an individual’s health and disease. As an example, a child with autism and ID was once tied outside to a tree so that evil spirits would not enter the family home.

The psychiatric professional using the biopsychosocial–spiritual approach (Lennox, 2007) needs to focus on details of all types of symptoms, and to sort them into categories of: (i) psychiatric disorder(s); (ii) medical/neurological illnesses, including possible seizures; (iii) medication-related side effects; (iv) environmental-related stressors. Thereafter, appropriate interventions, tests, or referrals can be made. Details to be clarified include any changes coincident with the time of onset or exacerbation of problems, and associated factors that improve or worsen the symptoms. Reliable caregivers’ input is vital in elucidating these clues.