The terms “mentally challenged” and “mentally retarded” are often used interchangeably to mean someone whose general intellectual functioning is significantly sub-average. According to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV), such a person may also show “significant limitations in adaptive functioning in at least two of the following areas: communication, self-care, home living, social/interpersonal skills, use of community resources, self-direction, functional academic skills, work,health and safety.”

Frequency And Onset:

Mental retardation may begin during the developmental period–from conception to age 18.

Levels of Mental Retardation:

There are different levels of MR, ranging from mild to profound. According to the DSM-IV, those with mild retardation are able to be educated and appear to be no different from children without mental retardation until their late teens. At the end of the spectrum, those with profound retardation may have a neurological condition that accounts for their disability. They are easily recognized in their early childhood and need special education in order to learn basic motor and communication skills.

Predisposing Factors:

The DSM-IV points out that in approximately 30 percent to 40 percent of people seen in clinical settings, there is no clear cause for the disorder. Heredity accounts for approximately 5 percent and includes genetic diseases such as Tay Sachs disease, Down syndrome and Fragile X syndrome. Chromosomal changes as in Down syndrome due to trisomy 21, or prenatal damage due to maternal alcohol consumption and infections, account for 30 percent. Fetal malnutrition, prematurity, hypoxia, trauma, viral and other infections are responsible for approximately 10 percent. General medical conditions acquired in infancy, environmental influences and other mental disorders make up another 20 percent.


There are no specific medications available for mental retardation in children or adults. The normal course of treatment for people with MR is a comprehensive management program involving a team of special educators, occupational therapists, speech language pathologists, physical and behavioral therapists and community resources. When other conditions coexist with MR, such as attention deficit (hyperactivity) disorder (ADHD/ADD), Ritalin and Dexedrine are commonly given to children.

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