This is really sad but being 31 she made a choice, Just don’t let any bad behaviours etc impact on your life.

I dont think there is much you can do. Is she willing to talk openly to you about it? If you push too hard to help her she may shut you out completely

She is an adult. Unfortunately you can’t do much about her decisions, even when they aren’t positive. Let her know that you are concerned, but love her regardless and support her. I may be wrong but LSD is not addictive and is not a drug that people, generally, use long term. If you are concerned further have a look at this link – it also links to further resources. https://adf.org.au/drug-facts/lsd/

I am sorry, I have no direct experience. However, I believe there is an organisation which specifically supports families of those who use drugs (similar to the one that supports families of alcoholics). I cannot remember their name, but your GP should be able to help.