This is considered income. You must file Form 1040 and include all of your winnings. Gambling income includes, among other things, winnings from lotteries, raffles, horse races, and casinos. It includes cash winnings and also the fair market value of prizes such as cars and trips.
Anyone who pays your winnings or awards you a prize is required to issue you a Form W-2G if your winnings are subject to Federal income tax withholding or if your winnings are over a certain amount.
So if your state pays your diability payments based on your monthly income, then yes, you may get less disability for a short time based on your gambling winnings.
http://www.irs.gov/taxtopics/tc419.html



