Defining: Mental Retardation

The American Psychiatric Association defines mental retardation (according to the DSM IV) as compromised intellectual function paralleled by a limited ability to perform daily living skills involving personal and social communication, independence, orientation, academic achievements, occupation, health and safety. One more factor needed to meet the criteria of mental retardation is that the condition was present before age 18.  According to the World Health Organization (ICD 10), mental retardation is a condition where inferior mental development is manifested in limited cognitive, language, motor and social abilities. According to the Welfare Act, a mentally impaired person is someone who has behavioral limitations due to impaired mental development.

Mental retardation is found in about 1% of the general population and 1.5 times more in boys than in girls. Because of accompanying health problems such as cardio-vascular disease, obesity, epilepsy and cancer, the death rate is greater among individuals with severe mental retardation than the general population. Risk factors for mental retardation may be organic, environmental and behavioral. The more acute the impairment, the greater chance there is to identify its cause.

Inferior intellectual function refers to an IQ lower than 70 (two deviations below average). Intellectual functionality is determined by psychological tests such as WISC-R, Kaufman, and Stanford-Binet. When a test is administered, the subject’s age, native language, cultural background and motor and sensory difficulties – if present – are taken into account.

There are four levels of mental retardation:

1. Mild mental retardation (IQ score of 50-70) – the individual’s cognitive function matches the age bracket of 9-12 years. Sometimes, mental impairment in such individuals is initially manifested as learning disabilities, occupational difficulties and a lack of social skills.
2. Moderate mental retardation (IQ score of 35-50) – the individual’s cognitive function matches that of child between 6-9 years. This type of impairment is manifested in delayed development in early childhood. Many individuals with this level of mental impairment go on to achieve basic academic and communication skills and attain a certain measure of independence and occupational aptitude, under various degrees of supervision.
3. Severe mental retardation (IQ score of 20-35) – the individual’s cognitive function matches that of a 3-6 year old child. He has minimal functioning skills and requires constant supervision.
4. Profound mental retardation (IQ score lower than 20) – the individual functions on the level of a child under three. There are significant limitations in mobility, independence and communication.

It should be noted that it is sometimes difficult to classify the accurate level of mental retardation in children and babies who do not cooperate well with evaluative tests.  

A treatment course is designed based on an evaluation of the individual’s needs and encompasses five aspects: intellectual enhancement, daily living skills, social skills, health care and community integration.  A comprehensive and professional plan involves stimulating, educating, and habilitating the individual so that he can fully utilize his potential. An effective treatment plan also provides ample support to the family.