Current use is still a problem AFAIK (not sure on weed).

That said I can confirm that a few years back a friend who had previously used/experimented with a wide variety of substances (EDM scene, psychs), had no trouble getting a clearance.

They disclosed all of it, said they weren't currently using it and wouldn't for as long as they were in the job role, passed the drug test, and that was fine.

That said, to add to the "lying is a bad idea" point: I believe some of their references were asked about if they'd ever known that friend to have a dependency + if they were aware of any current/very recent use.