Defining Mental Retardation

Defining Mental Retardation

Mental retardation refers to substantial limitations in present

Criteria for Mental Retardation

Significant Below Average Intellectual Functioning

Deficits in Adaptive Behavioral Functioning

Manifests before the age of 18

functioning. It is characterized by significantly below-average intellectual functioning existing concurrently with related limitations in two or more of the following applicable adaptive skill areas: communication, serf-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work (AAMR, 1992).

Mental retardation is further characterized as a fundamental difficulty in learning and performing certain daily life skills that involve the realms of conceptual, practical, and social intelligence. These three areas are specifically affected in mental retardation, whereas other personal capabilities such as health and temperament may not be. A score of 70 or below indicates below-average intellectual functioning.

Simply put, mental retardation can be identified by three criteria: significant-below average intellectual functioning, deficits in adaptive behavioral functioning, and manifestation of the condition before the age of 18.

Below-Average Intellectual Functioning

It has generally been recognized that only 3% of the general population has below-average intellectual functioning, but this group is greatly over-represented in prison. Offenders with mental retardation may well constitute at least 30% of the prison population. Of those with mental retardation, at least 85% to 90% are in the educable mild range with IQ scores in the range of 50-69. The remaining number of offenders is in the "moderate" and "severe" range, with IQs of 49 or below. Because all individuals are unique and have different strengths as well as weaknesses, a diagnosis of mental retardation does not imply that all persons in a given range will exhibit equal functional capacities. This diagnosis simply denotes the degree of difficulty a person has in learning.

Adaptive Behavioral Functioning

The second criterion necessary for determining mental retardation in a person involves limitations in the area of adaptive behavioral functioning. Limitations of this type must exist concurrently with below-average intellectual functioning, and they generally occur within the context of community environments typical of the person's age peers. In addition, these deficits generally indicate the person's individualized needs for support. Adaptive behavioral functioning refers to the behaviors that a person demonstrates while adapting to the environment. Limitations in adaptive skills are more closely related to intellectual limitations than to other circumstances such as cultural diversity or sensory limitations. Evidence of adaptive behavioral limitations is necessary because intellectual functioning alone is insufficient for a diagnosis of mental retardation. The AAMR's set of criteria requires that a significant disability in two or more adaptive skills areas must exist to justify such a diagnosis. The 10 skills areas are as follows (AAMR, 1992):

Communication. Comprehension of what has been said and the ability to express oneself verbally or non-verbally, as in gestures or through writing. Conversation may appear mundane, as much of what the person with mental retardation expresses is couched in childlike language that reflects his or her developmental age.

Self-Care. Possesses skills such as eating, dressing, toilet care, grooming, practicing hygiene, and other basic needs.

Home Living. Possesses skills such as cooking, budgeting, home care, housekeeping, house chores, and contacts with neighbors.

Social Skills. Demonstrates such skills as fostering friendships, appropriate sexual behavior, typical social exchanges with others.

Community Use. Includes the appropriate use of community services, such as knowing how to travel in the community and return home.

Self-Direction. Includes being able to follow scheduled activities, learning about the environment where he or she lives, making choices, asserting needs, and completing tasks.

Health and Safety. Involves a basic understanding of living a healthy lifestyle, preventing ill health, seeking treatment when appropriate, following safety rules, and being responsible for his or her own health.

Functional Academics. Possesses the ability to apply learned skills such as writing or the use of basic math.

Leisure. Involves doing recreational activities that are self-generated or part of a group.

Work. Can demonstrate the ability to hold a job, improve work-related skills, and interact with coworkers.

Manifestation of the Condition Before Age 18

The third criterion for mental retardation is that the condition must manifest itself before the person is 18 years of age. This age is used as a standard because it approximates the age when persons in American society typically assume adult roles after completing basic public secondary education. (The basic definition of a developmental disability does not include this criterion.)