Psilocybin Mushrooms as Hallucinogens Psilocybin Mushrooms are an example of a hallucinogen. They were originally used during religious ceremonies of ancient indian tribes. This was done to expand their minds. Today, you could say that mushrooms are used to expand people's minds, but definitely in a different way. There are many effects of using Psilocybin Mushrooms. Some are positive and some are negative. Also, the effects that psilocybin have on a person depends on how much they have had. There are quite a few minor effects on a person when taking a small dose of psilocybin (.25grams - 1.5 grams). They are things such as fatigue