Introduction and Nature of Mental Retardation (Intellectual Disabilities)

For Starters, a Terminology Note:

The term "Mental Retardation" (MR) is going out of favor as it has been judged to have acquired a negative and prejudicial meaning. It will likely be replaced with something along the lines of "Intellectually Disabled" or "Intellectual Disabilities" in the near future if that substitution has not (informally) happened already. This shedding of terms to describe the underlying phenomena associated with MR has happened before, and in all likelihood will probably one day happen again. No matter what the phenomena is called, some cruel people inevitably seem to find whatever terms are used to describe the phenomena useful as insults and taunts. We want to acknowledge the ongoing shift in the favored terms used to describe MR upfront. However, as our discussion is intimately linked with terms formally defined in the DSM (e.g., Diagnostic and Statistical Manual of Mental Disorders, currently in the 4th text-revised edition), our plan is to continue to use the term Mental Retardation until such time as the term changes with the publication of the upcoming DSM-V (5). At this time, Mental Retardation remains the formal and proper diagnostic term.

Nature of Mental Retardation

Mental Retardation is a diagnostic classification denoting significantly low intellectual functioning or other brain functioning problems. It is not a disease in of itself.

Classification of mental retardation indicates that developmental immaturities are present in the form of intellectual deficits, and often emotional deficits as well. This immaturity interferes with an individual's ability to function at age-appropriate levels and makes independent living a challenging proposition. A mentally retarded individual's cognitive abilities are impaired. This means that they acquire new information slowly and have difficulty understanding complex concepts.

Cognitive Functioning

Mental retardation is defined by sub-average intellectual ability. General intelligence quotient (IQ) scores for mentally retarded individuals are, by definition, seventy (70) or below. By definition, this score is set two standard deviations below the average IQ of 100, and only occurs about 2.5 percent of the time when considered against the entire distribution of IQ scores in the population. Because of these intellectual deficits, mentally retarded individuals' ability to learn is impaired. Language processing and logical thinking deficits are often present, as are impairments in reasoning and problem-solving abilities. Mental retardation interferes with language processing and impairs judgment and analytical skills.

Although the disorder affects an individual's capacity for learning, mental retardation is not a learning disorder in the academic sense. Mental retardation is distinguished from learning disabilities that are specific to academic learning such as dyslexia (a reading and writing disorder) and dyscalculia (a math disorder) in that it is more general in nature. In mental retardation, learning abilities are impaired generally, rather than in specific areas. Learning disabilities relate to specific deficits in the ability to acquire academic skills like reading and math, while mental retardation relates to basic and broad impairments in cognitive functioning that affect the individual's ability to process and retain information across the board.

Emotional Functioning

Mental retardation often affects people emotionally as well as intellectually. Many mentally retarded people function on an emotional and social level that is below what is appropriate for their age. This emotional immaturity is often considered an endearing aspect of mentally retarded individuals' personalities, however. Mentally retarded individuals are commonly thought of as being friendly, lovable, and possessing a child like quality in their overall personality.

The emotional maturity of individuals who are diagnosed with mental retardation is generally a function of how severely impaired they are. Severely mentally retarded individuals are generally more emotionally immature than are individuals with mild mental retardation.