How many people have mental retardation

Your member credentials do not work with the login widgets on these pages. Sign In or Create an Account. User Tools. Sign In. Skip Nav Destination Article Navigation. Close mobile search navigation Article navigation. Volume , Issue 3. This article was originally published in. Previous Article Next Article. Article Navigation. Research Article May 01 Larson ; Sheryl A. Although all persons with mental retardation have significantly impaired mental development, their intellectual level can vary considerably.

An estimated 89 percent of all people with retardation have I. For the lay person or non-specialist, the significance of a low I. That is, he cannot perform intellectual tasks beyond the capacity of a typical ten-year-old. According to a psychologist who evaluated Mata, "his ability to express himself and his ability to recognize the meaning of common words were at the level of a nine- to ten-year-old child He lacked basic understanding of familiar processes.

He did not know the function of the stomach, where the sun sets, nor why stamps are needed on letters Arithmetic abilities were limited to addition and subtraction with the help of concrete aids such as fingers. The threshold I. Limitations in adaptive skills. Mental retardation entails significant limitations in two or more of the basic skill areas necessary to cope with the requirements of everyday life, e.

He or she may have trouble sitting or standing still, or may smile constantly and inappropriately. Limitations in everyday coping skills may be more or less severe, ranging from individuals who can live alone with intermittent support, to individuals who require extensive hands-on assistance and guidance, to individuals who require constant supervision and care.

For most people with mental retardation, limited adaptive skills make ordinary life extremely difficult unless a caring family or social support system exists to provide assistance and structure. Offenders with mental retardation who have been convicted of committing capital crimes typically grew up poor and without networks of special support and services -- often without even a supportive, loving family. They functioned as best they could without professional assistance, often required to fend for themselves while still teenagers.

If they were able to work, it was at basic menial tasks. After being hired as a kitchen dishwasher he was fired when he could not learn to operate the dishwasher.

Family members reported that "if one told Billy exactly what to do and took him to the place where it was to be done [he] could do some work. If he were left on his own and not specifically guided, he could not do it. Manifestation before the age of eighteen. Mental retardation is present from childhood. It can be caused by any condition which impairs development of the brain before, during, or after birth. The causes are numerous: hereditary factors; genetic abnormalities e.

Down's syndrome ; poor prenatal care; infections during pregnancy; abnormal delivery; illness during infancy; toxic substances e. Regardless of the cause, part of the definition of mental retardation is that it manifests itself during an individual's developmental period, usually deemed to be birth through age eighteen.

Many psychiatrists argue that the age before which signs of retardation must become manifest should be raised from eighteen to twenty-two, to reflect the difficulties in obtaining accurate age records for many people with this disability and the differing rates at which people develop. An ordinary adult cannot suddenly "become" mentally retarded. An adult may, for reasons related to accident or illness, suffer a catastrophic loss in intellectual functioning and adaptive skills, but this would not make him or her "mentally retarded," since by definition mental retardation starts during childhood.

One implication of this is that mental retardation is virtually impossible for an adult to fake: when evaluating whether an adult is mentally retarded, testers look not only at I.

Early diagnosis can help the person with mental retardation obtain access to appropriate special education, training, clinical programs, and social services during important developmental years -- as well as through life.

With help from family, social workers, teachers, and friends, many mentally retarded people succeed in simple jobs, maintain their own households, marry, and give birth to children of normal intelligence.

There is no "cure" for mental retardation. Characteristics and Significance of Mental Retardation. Although mental retardation of any degree has profound implications for a person's cognitive and social development, it is a condition which in many cases is not readily apparent. While some of the mentally retarded, such as those whose retardation is caused by Down's syndrome or fetal alcohol syndrome, have characteristically distinctive facial features, most cannot be identified by their physical appearance alone.

Unless their cognitive impairment is unusually severe e. Many capital offenders with mental retardation did not have their condition diagnosed until trial or during post-conviction proceedings. A person with mental retardation, according to one expert, "is always the least smart person in any group. This leads to fear, dependence and an experience of terrible stigma and devaluation. They may wrap themselves in a "cloak of competence," hiding their disability even from those who want to help them, including their lawyers.

At times, even competent lawyers who are anxious to help their clients may fail to identify their clients' retardation or may be unable to access funds for a psychological evaluation. Cruz nonetheless insisted to reporters that, although he was perhaps "slow in reading, slow in learning," he was not mentally retarded. He had gone through much of his schooling allowing his younger sister to complete his homework for him.

When he was given papers to read in connection to his case, he would carefully stare at them. If he was asked a substantive question, he usually responded, "I don't recall.

He lied about finishing high school. He was actually in special education classes and did not finish the sixth grade. To be eligible to receive SSA benefits for MR and, therefore, be included in the SSA database , adults must have had an intelligence quotient IQ of less than or equal to 59 or an IQ of with other physical or mental impairment s resulting in additional and substantial work-related limitations of function.

All persons receiving SSA benefits also must meet income-resource eligibility requirements 4. The numbers of children and adults identified through DOE reports and the SSA database in each state and the District of Columbia were combined to estimate the total population with MR.

Prevalences of MR were calculated for children by using the total number of children aged years in each state and for adults, by using the total number of persons aged years. The census was used as a source for state population estimates and demographic data i.

Multiple linear regression was used to determine the amount of variability in the state MR rates that could be attributed to those three socioeconomic factors. In , an estimated 1. State-specific rates varied approximately fivefold range: 3. The states with the lowest rates were in the Pacific and Mountain regions. For children, the MR rate was For adults, the rate was 6. The correlation between state-specific rates for children and for adults was 0.

Low educational attainment was the most important correlate of MR rates among adults. Editorial Note: This analysis of data from entitlement service programs suggests wide variation in state-specific rates of MR for children and adults in the United States. Use of this method of monitoring the prevalence of MR can assist in evaluating temporal trends and in identifying high-risk areas within states.

The high rates of MR documented in the South Atlantic and East South Central regions are consistent with rates for disabilities from all causes, which also indicate wide variations among the states 5.

In addition, the finding that a substantial proportion of state-specific variation was associated with differences in median income, percentage of births to teenaged mothers, and percentage of adults with less than a ninth-grade education is consistent with previous reports documenting the relation between the prevalance of MR and socioeconomic factors 6 , particularly low maternal education levels 7.

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Practical Diagnosis. Feb 15, Issue. Identification and Evaluation of Mental Retardation. Mental retardation in young children is often missed by clinicians. TABLE 1. TABLE 2. TABLE 3. TABLE 4. Read the full article. Get immediate access, anytime, anywhere. Choose a single article, issue, or full-access subscription. Earn up to 6 CME credits per issue. Purchase Access: See My Options close. Best Value! To see the full article, log in or purchase access.

More in Pubmed Citation Related Articles. Email Alerts Don't miss a single issue. Sign up for the free AFP email table of contents. Navigate this Article. Function at one half to two thirds of CA IQ: 50 to Function at one third to one half of CA IQ: 35 to Function at one fifth to one third of CA IQ: 20 to Noticeable delays, especially in speech. Marked and obvious delays; may walk late. Marked delays in all areas.

May have no unusual physical signs. May have some unusual physical signs. Congenital abnormalities often present. Can acquire practical skills. Can learn simple communication. May be taught daily routines and repetitive activities.