For all individuals under title II and adults under title XVI, the Act defines disability
as:
“The inability to engage in any substantial gainful activity by reason of any medically
determinable physical or mental impairment which can be expected to result in death
or which has lasted or can be expected to last for a continuous period of not less
than 12 months.”
In title XVI child cases, the Act defines disability for an individual under the age of 18 as:
"a medically determinable physical or mental impairment, which results in marked and
severe functional limitations, and which can be expected to result in death or which
has lasted or can be expected to last for a continuous period of not less than 12
months."
NOTE: To find a person disabled, their medically determinable impairment(s) (MDI) must
meet the duration requirement.