Be very careful when dealing with hallucinogens like magic mushrooms. While they pose little danger to your physical health, your mental health could be compromised, especially if you are already a person who isn't well balanced and very comfortable with who you are and with the environment around you. (Of course, it begs the question, if you already are well balanced and very comfortable with who you are and the environment around you, why would you need to try something like this?)
If you believe you are more likely than others to ever develop mental problems such as schizophrenia and paranoia, be extra careful and probably avoid hallucinogens altogether. I've seen people do harm to themselves and develop increasingly distorted personalities when using these substances.
Don't assume that just because HG tribes used them in shamanic rituals and that it may or may not have helped them, that they will help you, in a completely different environment, with completely different goals, and without experienced shamans to guide you through the experience.
By the way, the "non-addictive" (resistance forming) nature of hallucinogens has nothing to do with them being natural or artificial, you can no more become addicted to LSD than to magic mushrooms.
