drug abuse in the oilfield is huge in the US. You show up on a rig right now to do a random drug test and the crew will just walk off the job, go to the next rig.
Knew someone that went out to a rig the other day and it was sitting there with the bit off bottom just rotating. Not a soul around.
Also, had a high school kid here that went to work for a small roustabout company that did not drug test. He said for 1 hr before every job, his crew sat in the truck and smoked weed. I told him to get the fuck out of there before he died.
This work is dangerous enough with your head clear.