>>310532I'm not the master of psychedelics or anything, but I've tried both of the major classic psychedelics a handful of times.
Mushrooms would probably be your best bet. Don't go overboard, though. I haven't had a bad experience with them yet, but I also didn't take 10 grams of them or something. They tend to be sedative, so it'd probably help some.
Personally, I wouldn't recommend LSD for you. I've had good experiences with it, but it seems to be much more sensitive to set and setting. It also makes me more paranoid as a general rule, and I can't imagine that being good when combined with OCD. It also lasts for a pretty long time, and it's way harder to sleep on (if not completely impossible). Taking it at ~11 PM means you're not going to bed until 8 or 9 AM.
And, yes, set and setting are important. Moreso for LSD, but you shouldn't just ignore it. If you have any anxiety about anything at all, it'll probably be a problem. For instance, if you think someone is going to interrupt you, that will be a problem. Generally, you don't want to be around people. It might be useful to talk with someone (doesn't have to be in real life) but it's not necessary, as long as you aren't doing anything stupid it should be fine.
It's hard for me to really tell you how effective they'll be for your OCD, since I don't have OCD myself, but they could help. After all, they do change how your brain works temporarily. Just don't do it if your family has schizophrenia or some other mental illness since it can awaken that in you earlier than normal.
In terms of safety, you only really need to be concerned about the psychological aspect unless you take LSD (there are rare but not unheard of substitutions for LSD that taste bitter, and have negative effects). The lethal dose for both mushrooms and LSD is likely far too expensive for you to even reach. I've also never heard of anyone spiking mushrooms with anything. However, you do need to be in a stable mental state. I wouldn't want to be the one to find out what happens if you aren't.