Social Security Disability Insurance: Participation Trends and Their Fiscal Implications, July 22, 2010 – “The Social Security Disability Insurance (DI) program pays cash benefits to nonelderly adults (those younger than age 66) who are judged to be unable to perform “substantial” work because of a disability but who have worked in the past; the program also pays benefits to some of those adults’ dependents. In 2009, the Disability Insurance program paid benefits to almost 8 million disabled beneficiaries and about 2 million of those beneficiaries’ spouses and children.”