I had a friend who took a "spread" of crystal lsd across a matza cracker and ended up having a psychotic break, or what most would term a psychotic break anyhow. He described seeing people as balls of light for nearly 6 months, and he had very little control over when this happened. He also become very paranoid that one of the people amoungst his circle of hippies was an "fbi agent" and at one point a friend's iguana had become a :cia mindops agent" that was communicating to him through brain waves. Now, this all happened several years before I met the guy, and he continues to exhibit signs of paranoia till this day (nearly 12 year later). At new years eve 2000, he was with me and we took lots of acid together at a phish show, along with e, cactus powder, and weed. He ended up having another meltdown, and this time I became the cia agent in his mind, but a few hours later he told me that he thought he was the cia agent and that all the drugs over the years had confused him...reminded me of PKD...he seems much better these days, but I think that the crystal lsd did him in. I didn;t know him beforehand, so I can;t say if I think he had latent issues that were brought to the surface...but most of us humans do.
Despite all that I would try a thumbprint myself...I am only gonna live once. I have a similar philosophy about trying heroin. I know I would love it and want it all the time, so I will not do it until I am old, maybe at say 75 I will go and start shooting some smack.