Do programs like D.A.R.E. work?

This is red ribbon week at my children’s school. They are being taught all about illegal drugs and how to say no. I have always been dubious about programs such as these being presented to very young children. That feeling was confirmed for me when my first grader brought home a red ribbon he had made of construction paper; on it he had printed “Just Say Now to Drugs.” Parents did your kids go through these programs? Did they stay drug free? If you went through one, what do you think of programs such as these?