tell them about my drugs problems ?
Many companies have a ZERO tolerance policy towards such things. I'll maybe do 0.5 mg or something as a compromise. My adrenalin will be flowing so much it wont be noticebale, other than 'he looks calm and collected and confident', not 'he looks out of it'. That was my experience during the counselling course i attended, it didnt impair me at all, made the simple act of talking to strangers so much less uncomfortable.
Whenever I've admitted to having serious drug and addiction issues to an employer I must admit they've tended to greatly surpass my expectations. Had a job as a lace-cutter in a lingerie factory for a while (some of y'all lay-deez may just have had some of my handiwork carressing yer nips 'n' gussets back in the mid-90s

) and was as settled as I could be at the time. Which meant at least three (often four) days off each week cos I was clucking so hard I couldn't do anything other than sweat profusely and watch the seconds crawl by til wages went in at the end of the week and I could score again. And the days I was in I was nodding so hard the gals would have to give me a nudge to bring me round if a manager came down or it was break/lunch time. Would go in in the morning barely able to lift my head nor keep both eyes open long enough to stop seeing double (which made lining up fiddly bits of lace quite the challenge

) and often get a couple rocks on tick at lunchtime so be bouncing around in a wild-eyed sweaty frenzy in the afternoons.
It seemed so blindingly, unavoidably obvious that I was permafukked yet nobody ever questioned or queried my somewhat quirky behaviour and manner. As I said, the other gals would literally just give me a nudge if they thought I should probably be vaguely conscious for anything. Never asked why - didn't even hear any gossip or owt, but maybe I wouldn't have been aware if there was. I wasn't aware of much of anything other than the ever-present balancing act of when and where the next dig was coming from and/or had just been had, As such, I almost started to feel kinda guilty at messing them about cos you get to know folk a bit and they were a decent bunch whilst I was taking the piss. So, after taking a good 2-3 weeks straight or so off because I could and nobody was querying what I was or wasn't doing, I decided I'd best talk to the manager about it cos I clearly wasn't actually capable of doing what was expected of me but nobody seemed to have noticed or were too polite (or perhaps baffled and bemused - intimidated even maybe cos drugs can look scary from the outside and especially so when done so very, very intensely and unremittingly).
I basically told the manager that I had a heroin problem and that's why I'd not been in at all for the previous couple weeks and hadn't bothered to phone in or anything to say owt about all this time off. Ya know what? He was soooooooooooooooooo nice about it. Refused to sack me even though I asked him to (or suggested that he probably should because I was truly incapable of meeting even a handful of my supposed work duties and tasks). Instead he insisted that I take as much time off as I felt I needed, get in to see a doctor or specialist about the heroin/crack addictions, suggested seeing either my own doctor or one of the company's docs about related mental health issues (primarily stress, anxiety and depression) and just bent over backwards to try to help me or to at least provide the space and time to work out what exactly I intended to do cos abuse at that level is simply unsustainable and I was bursting out at the seams all over the place. And all whilst still receiving my normal week's wage whether I made it in at all or not. He was actually so generous, thoughtful and kind that I had to resign not long after cos I knew I was just stringing 'em along to get money in my account each week for doing fuck all of much beyond nodding whilst operating heavy machinery.
Bit long-winded, granted, but the possibly relevant bit is that people will surprise you how much they want to help if they feel you really need the help. Admittedly it's probably not ideal to bring anything like that up at the interview stage
But basically, give people a chance to be decent, kind and considerate and they'll often exceed your every thought and expectation. People are great and don't get told it often enough. People as a whole and as individuals. Great so they are. Except the ones that aren't but they're mostly just insecure and could do with some help themselves.
/work/drugs-related ramble