Here is a wonderfully helpful post by guest blogger, Ram Meyyappan from The Social Security Disability Help website
Applying for Social Security Disability with Depression
Severe depression can make it impossible to maintain employment, or at least to maintain gainful employment. If you suffer from persistent depression despite receiving appropriate treatment and following prescribed therapies, you may be able to receive disability benefits through one of both of the Social Security Administration’s (SSA’s) disability Programs:
SSDI and SSI Basic Eligibility
Both SSD programs require you have a persistent and severe medical condition that prevents you from maintaining gainful employment. SSDI also requires you have work credits built up from your employment history. SSI, on the other hand, has no work credit requirements, but is instead a need-based program with strict income and financial resource limitations.