Anxiety and the meditative state are, to put it simply, impossible to experience at the same time. Who is it that is anxious, when that anxious person no longer exists?
The common thing to point out on these kinds of anecdotes are the "started at 1# and I'm 2# now" part of it. I started at 23! Didn't even bother drinking until 21! This is what all the studies are about and usually are conclusive about - the brain is still forming in these years, and you really should wait. (Although, in my opinion, the legal age for both should be 18). My advice for the "did I lock the door" / "did I leave the coffee maker on" issues is this: create habits and follow them. Unplug the coffee maker. Either the door is wide open, or it is locked. Either your keys are in the spot where the keys always are, or they are in your pocket. You have to be able to trust yourself.
You're dropping real facts, no one should argue against these very real risks, and I do know people to whom this is absolutely accurate. I can see this playing out, which is why I don't follow through with it. Myself, I haven't smoked in over a month, because I can take it or leave it. I've worked with the "smoke before-work, at-lunch, after-work" types. I've been interviewed by people who later smoked with me, because everyone does it. It makes you delusional, it makes you lazy, true, true. I've git clone'd code and then edited code formatting pointlessly, just like you. And yet, still better than most of them, somehow. Just walk through the door and, if you can, leave the door behind.
I'm speaking from personal anecdotes only. The only downside to me is that it suppresses REM sleep, leading to dreamless sleep. This is kind of boring. It's also more difficult to learn something for the first time while high. Don't go to a poker game high and try to learn the game, for example. Psychosis? Not a factor for me, so I'm not attempting to say one thing about it. Extrinsically, there's all of the legal/job related annoyances in additional to dealing with losers who won't do anything without it.
Weed (because it has no real downsides to me personally) and once-a-year DXM (for depersonalisation) were mildly effective, but the clincher has been learning about buddhism / the tao. I'm not talking about any kind of spiritual practice, but moreso a change in perspective that simply isn't expressed by anyone around me. Doing the unambiguously right thing in the best way in any circumstance with no effort or conscious thought is powerful. I started with the question "How do I talk to people correctly?" and found "right speech" and went from there. Nearly two years later I can say it's been transformational at lowering the anxiety that I once had. Automatic negative thoughts happen infrequently instead of constantly. Though, this is not setting me up to be rich and with lots of worldly possessions or friends, but I'm alright with that.
edit: disappointing that all of the replies are about the first word in this post, but I kind of asked for it. Talk about whatever you want to talk about.