Borderline intellectual functioning is a cognitive impairment that applies to people who have lower than average intelligence but do not have intellectual developmental disorder or mental retardation. Borderline intellectual functioning is diagnosed by IQ test scores that are between 71 and 84. People with borderline intellectual functioning typically have difficulties with learning, reasoning, planning, abstract thinking, and judgment. Lower than average intellectual functioning can be caused by birth injury, fetal alcohol syndrome, environmental exposure to toxins such as lead, infections, or genetics.
In general, borderline intellectual functioning by itself is not enough to be found disabled under the Social Security Act. But in combination with other mental or physical impairments, borderline intellectual functioning can qualify someone for disability benefits.
Qualifying Under a Disability Listing
The impairment listing for mental retardation in Social Security’s "blue book" requires an IQ of 70 or less to award disability for mental retardation. (See our article on disability for mental retardation or traumatic brain injury). But an applicant with a slightly higher IQ, such as 71 to 75, who also has other physical or mental disorders, may qualify as disabled if the agency finds that the combined effects of the applicant's other impairments are medically equivalent to (just as severe as) mental retardation. (For more information, see our article on how Social Security uses the blue book listings.)
Applicants with borderline IQ scores should submit their IQ test scores to Social Security, making sure to include information about the standard deviation of the IQ test that was used. The standard deviation could indicate that test scores tend to be high and may not fully reflect the applicant’s disability. It is also a good idea to include school records, testimony from teachers or supervisors, and other evidence that shows a higher level of impairment than the IQ score alone might suggest.
Qualifying through an RFC Assessment
An applicant with borderline intellectual functioning who does not qualify for disability through the mental retardation listing may nonetheless be able to qualify for disability benefits by proving that his or her impairments make it impossible to find full-time work.
Social Security assesses an applicant’s mental limitations to come up with the applicant’s "residual functional capacity,” or “RFC.” The RFC is then used to determine whether there are any jobs the applicant can do despite his or her limitations. A mental RFC includes non-exertional limitations, such as the following:
Following instructions. Applicants with borderline intellectual functioning may have a limited ability to understand, remember, and carry out complex instructions. They may require that tasks be broken into individual steps that can be completed one at a time, rather than being given a series of instructions that must be remembered and followed one after another.
Supervision and training. The need for close supervision and/or an extended training period is another, related limitation. A person with borderline intellectual functioning may not be able to do any of the jobs that don't provide much support from supervisors.
Concentration. People with borderline intellectual functioning may also have limited ability to concentrate and focus. They may need to avoid multitasking, or doing several things at once. As a result, they may be limited to jobs that involve only simple, routine tasks. Evidence of difficulties with concentration may be found in work evaluations that show frequent errors.
"Pace" is another workplace limitation that may apply to someone with borderline intellectual functioning. Someone who needs extra time to perform tasks may not be able to do certain jobs, such as assembly-line work.
Judgment. Because people with borderline intellectual functioning often have impaired judgment and reasoning ability, they may have a limited ability to make judgments on complex work-related decisions. This is another potential workplace limitation that should be included in the applicant's RFC, if applicable.
Social functioning. Borderline intellectual functioning often causes difficulties with social functioning and communication. Someone with this condition may be unsuited to jobs that involve dealing with customers. This should be reflected in the RFC as a limitation in contact with the general public.
A person with borderline intellectual functioning should gather as much evidence of these limitations as possible when applying for disability benefits. In combination with limitations caused by other physical or mental medical conditions, they may qualify someone for disability benefits. For more information how Social Security assesses whether an applicant's limitations rule out work, see our article on how Social Security uses mental RFCs to assess disability.