JohnN--don't rule yourself out yet.  I've taken polys for 4 intel agencies and have passed 3 of them.  The other, FBI, I'm waiting for the results.

I've never done drugs, but each polygrapher has accused me of it and hounded me.  One of them even had no problem with the drug question for me, but said I was failing the question of selling.  I guess I don't use, but I sell.  Not.

I took the FBI polygraph last week.  I'll describe it in it's own thread.