The food stamps and medicaid wouldn't prevent them from being your dependent.
You can claim your adult son or daughter if they are your qualifying relatives. To be a qualifying relative (i.e., a dependent),
- you must provide more than 1/2 of the individuals support,
- they must not earn more than $3,900 of income subject to tax in 2013 (social security doesn't count)
- they must not file a joint return with another
- If not an actual relative, they must live with you all 365 days of the year, and
- they are not a qualifying child of another taxpayer.
Also, all dependents must be citizens of the US, or residents of the US, Canada or Mexico.
You can claim their children (your grandchildren) that live with you if your son or daughter does not claim them, they live with you more than 1/2 of the year, and your income is higher than your child's income. Alternatively, you can claim them if they meet the same criteria as your child above.
Dependents are added under the personal info tab.
The dependent interview has changed in 2011. In the Turbotax interview it asks your relationship to your dependent. Do not select that your grandchild is your child, but do select the other option - i.e., that the dependent is someone else that you support. That should give you the opportunity to click on a drop down list that includes brother, sister, aunt, uncle, niece, nephew, grandchild, grandparent or other.
