Researchers say drug testing students might not reduce the use of marijuana. In fact, it's possible the opposite is true.

Researchers with the University of Pennsylvania and in Israel say they looked at recent studies on the effectiveness of drug testing in schools.

They say it appears in most cases pot use didn't go down in schools where student were drug tested -- in some studies use of pot by boys actually went up with testing.

The researchers conclude reducing pot use has more to do with open communication policies in schools which encourage parents, teachers, and students to trust and talk.

However, there are schools with such policies and testing that work, so it could be how the testing is handled.

Drug Testing Study