The inability to engage in substantial gainful activity (SGA) by reason of any medically determinable physical or mental impairment that can be expected to result in death or to last for a continuous period of not less than 12 months. (Special rules apply for workers aged 55 or older whose disability is based on blindness. The
Individuals are considered to be disabled only if their physical or mental
The SGA criterion does not apply to children under age 18 in the Supplemental Security Income program. The standard for them is a medically determinable physical or mental impairment that results in marked and severe functional limitations.