As we have found out recently with Benoit, the WWE tests arn't 100% correct. I don't think that the companies are to blame. TNA also brining in a drug pollicy. The big 2 are doing thier due dilligence. I fully think it's the wrestler's responsabilities to do the right thing, and change thier ways. Back in the 80's and early 90's back stage was like a rock concert, drugs and women everywhere. Ted Dibaise stated that in a recent interview on CNN. There are definatly more drugs than just roids, as the media is leading people to believe, involved with these deaths, Curt Hennig (Mr. Perfect) died from a cocaine OD in the toxology report.
http://en.wikipedia.org/wiki/Curt_Hennig
I wouldn't be at all surprised if it would be the same for Brian Adams