Should People Have to Pass a Drug Test Before Receiving Welfare?

Not too long ago, an email forward was sent to me that made me think.  It brought up an interesting point about how those of us who are gainfully employed are often subjected to urine tests for illegal substances and other "checks", if you will.  Passing them is required in order to get the job, aka to earn a paycheck.  If our taxes go to those receiving assistance from the government, shouldn't or DO those individuals have to abide by the same "screening" processes before they qualify to receive money?