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Mental retardation is a term that has been widely used to describe people with less than average intelligence and behavior problems. However, the term "retarded" is sometimes viewed as derogatory, and other terms such as mentally handicapped, disabled, or challenged are often used. Regardless, all these terms refer to the same syndrome of less than average intellectual ability caused by a biological problem leading to a brain defect. This problem is related to genetic abnormalities (inherited) or difficulties early in development (before or after birth), which means that mental retardation in older adults is usually a continuation of changes that began earlier in life.

The number of older adults with mental retardation is increasing, because life span is increasing. Life expectancy of mentally retarded people increased from 20 years in the 1930s to 60 years in 1980. Average life expectancy has increased by about 30 years for those with Down syndrome, which is the most recognizable form of mental retardation. Current estimates suggest that more than one half million Americans over the age of 60 are suffering from mental retardation. This number is expected to double by 2030.

Mental retardation is associated with many problems. Research surveys suggest that 25% of mentally retarded adults have no useful speech, and that 10% lack basic comprehension skills. Approximately half of retarded adults cannot care for themselves, half have a physical disability, and half have problems getting around. These problems tend to increase in later life, because of continued mental decline and loss of mobility associated with age. One out of every 10 mentally retarded adults is totally dependent on others.

Over 75% of adults with mental retardation live at home and are cared for by aging family members. This often leads to a crisis when parents are no longer able to provide adequate care or cannot manage a behavioral problem. Unfortunately, many families do not make plans for the future care of adult relatives with mental retardation, and social services are typically inadequate to cover all the needs of these individuals.

• Disorders Associated with Mental Retardation in Aging Adults
  • Dementia
  • Behavioral disorders
  • Medical problems
• Diagnosis and Treatment

Mentally retarded individuals may develop a wide variety of mental or physical problems as they age. Psychiatric disorders are about five times more common among adults with mental retardation than in adults of the same age. In mentally retarded adults aged 65 and over, approximately 75% have a major psychiatric problem. Autistic traits are common, occurring in up to half of adults with learning disability or mental retardation.

Dementia is a common problem associated with mental retardation. Adults with Down syndrome have an especially increased risk of early onset of Alzheimer's disease, with nearly all developing characteristic nervous system changes by age 40. After age 50, almost half of those with Down syndrome have symptoms of Alzheimer's disease. In addition, about half may have seizures (see also Dementia and Diseases of the Nervous System). Approximately 75% of people with Down syndrome have symptoms of dementia before they are 70 years old. Early age at menopause may be a risk factor for early dementia among women with Down syndrome. Mentally retarded adults without Down syndrome also have an increased risk of Alzheimer's disease.

Common symptoms of dementia among those with Down syndrome include loss of ability to adapt and increased episodes of being agitated or aggressive. This dementia is often associated with depression, indifference, and socially inappropriate behaviors.

Many adults with mental retardation have behavior problems, such as withdrawing from others, injuring themselves, acting aggressively, or repeating a specific behavior over and over. These problems are often severe and may go on for years. Problem behaviors are often preceded by a change, such as moving to a new environment or losing a familiar companion. Mentally retarded people have limited coping skills, making it more difficult for them to adjust to changes in living or work situations.

Adults with mental retardation have more medical illnesses than other people of similar age. Approximately two thirds of those living at home have long-term medical conditions or major physical disability. In general, the average retarded person has approximately five medical conditions. Those with more severe mental retardation often have more medical problems. It has been estimated that half of these medical conditions go undiagnosed.

Having other medical conditions decreases the life expectancy of mentally retarded adults. Average life expectancy of adults with mental retardation is 65 years, which is considerably lower than that of the general population. The most common causes of death are heart disease, respiratory disease, cancer, and dementia.

Prompt detection and treatment of mental or medical conditions improves the life expectancy of mentally retarded adults. Although the basic approach to the diagnosis and treatment of illness is no different than in anyone else, the process can be more complicated in someone who has mental retardation. For example, people with mental retardation typically have poor verbal skills, making it difficult for them to express how they feel or what they are thinking. Instead, mental illness often shows up as changes in behavior. For example, clinical depression may show up as withdrawal or lack of interest or response. Delusions or hallucinations may be seen as agitation, sleeplessness, or aggression. Medical problems such as chronic pain may also show up as behavioral problems in people with mental retardation.

An accurate diagnosis is easier if the cause for the retardation is known, because different conditions are associated with different problems. Careful physical and laboratory evaluations, along with sophisticated neurologic tests can be used to determine a cause in nearly half of the cases. Older adults with mental retardation who develop further intellectual deterioration or behavior problems may benefit from referral to a specialist for assessment.

Appropriate treatment depends on the underlying physical or mental problem. The approaches used to treat psychiatric problems are similar to those used for people without mental retardation. These include both behavioral therapy and drug treatment. Of course, mental limitations may make treatment more complicated in adults with mental retardation.