Yes I smoke weed. No I don't smoke nicotine. I try to vaporize to be a tad healthier, less carcinogens that way and so on. Yes I drink occasionally, but not to get drunk. Smoking as much as I do means I don't get messed up unless I smoke a lot at once -- which happens at the odd party, or if I'm celebrating.
Psychedelics, I've tried a few, and enjoyed them, but you really have to plan ahead for that and be sure you're not going to miss something important or fuck something up.
I'm a rather anxious / nervous person in general, and weed makes me much less paranoid than I usually am. I'm well aware this is the opposite of some peoples' experiences.
When I was younger I was really paranoid about the idea of chemicals that could change the way I think and perceive the world around me. I liked to think that I at least had control of my thoughts, if not much else in my life. Trying marijuana made me realize just how little control we ever have, even when sober. I became aware of how my mood was affected by the weather, or watching the news; and I became more conscious of how others attempted to manipulate me through affecting my mood or playing with my ego. That realization helped me stabilize my personality in a big way and is something that changed me permanently.
On the other hand I did use it as a crutch when I got back from a short volunteer trip to Calcutta & Varanasi that really messed with my head. One side effect of heavy pot smoking is that your dreams become less pronounced, and I used that to curb my nightmares of drowning in the Ganges. I don't know if it was the pot or just my overall apathy that made me slack off so much in my first years of university, but I like to think that as long as you're not one of those people who have nothing in their lives but a certain set of substances, there's hope for you yet.
These days I still smoke nearly daily (oh, who am I kidding, it's a daily habit) but not until the
end of the day, once I've gotten some important things out of the way. I still wake'n'bake fairly often on the weekends. Having a girlfriend who doesn't smoke helps to restrain me, though she's in no way judgmental (she can drink me under the table and believes in personal freedom besides) and I do appreciate that. Being strapped for cash also helps, as I'm not so irresponsible as to borrow money to spend on drugs.
But after all that (and I've practically written my biography), how does weed affect my high scores? Well, as far as I can tell (and I've tried to test this scientifically) it doesn't. Now being such a pothead I obviously play more often high than not (I mean, it's my relaxation activity), but I've played plenty of sober rounds and the odd drunk one and I play fine completely baked; not to mention the fun I've had zoning out to crazy bullet patterns; meanwhile, even being a bit tipsy messes badly with my concentration and reflexes. Chalk it up to whichever chemical you're most used to, I guess?
As for how I am right now, well, I wish I could be all like "I am so high right now, I don't even know what's going on" but I didn't have much pot to smoke, just a roach in the afternoon. So after class I smoked that and went out to vote (no, not for the marijuana party...), came back and studied for Friday's midterm for between four to six hours, broken up by making dinner for the .gif, and now I'm sipping whiskey and about to go back to playing shmups. It's been a good day all in all, and productive, natch.
I guess a part of me wanted to write a nice long blog post just to show that pot-heads can spell and even use punctuation too.

No offense to jon... and not that I'm anal about my grammar or anything. Must ... not ... end ... on an ... unstressed ... syllable ... NOW!