Known a number of people who have gone over a 1/4 ounce of dried mushrooms in a session. None of them reported any unexpected side effects or long term issues.
I should point out that in this group of people "unexpected side effects" did NOT include any of the following:
Things that once seen were never able to be forgotten
Periods of inability to communicate with anything animate
Repeatedly getting lost... while sitting
The total lack of recognition of one's own body parts/voice/thoughts
The inability to recall how to operate; zippers, doors, hats, pencils...
Receiving the horrific knowledge concerning one's immanent demise at the hands of an unspeakable entity for being so foolish as to have done what they did.
Having their soul/mind/world view, shredded to pieces and reassembled in a different pattern then it was to start.
Reintegration process lasting weeks, if not months
Discovering what you wanted and what you NEED are two very different things
Discovering what you wish to be doing and what it is you NEED to be doing, are not only different things, but often at complete odds with each other.
Long term effects that were ALSO NOT unexpected:
Total change in paradigms
Loss/gaining of religion
Rather drastic changes in life goals
Feeling uncomfortable dealing with people who have not gone through that sort of ordeal
Other people feeling uncomfortable with you
Alienation from friends, family, loved ones, pretty much everyone who doesn't share your new world view, and even those who do.
Difficulty finding meaning in activities you are used to doing.
These lists go on and on. What I am getting at, is the people involved, knew what they were getting into, they understood this was not a game, but an ordeal, one with great rewards, but one that comes with a price. These events were well planned, the yoga's and rituals started days, weeks, months, years ahead of time. Body's and minds were trained and disciplined so as not to break in the wrong way...yes, you WILL break, the question is do you become a holy man or a babbling idiot?
I can not recommend this for anyone, especially with out further background into their education, practices, beliefs, mental/emotional history, physical world living situation, there's too many factors at play. The people mentioned above, were by and large, free of all responsibilities at the time they undertook this ordeal. They had the time to come back, reintegrate, deal with what they had learned, learned how to deal with the world again. They were not alone in their ordeal, having not only each other, but other initiates and loved ones who understood what they were undertaking and were willing to support them through the process. Tripp sitting doesn't end when the drugs effects are done, but when the person is back to ground state, in this case, it was quite some time after the event.
I should also point out that all these people are considered, by and large, to be madmen, ner-do-well's, disappointments to their families, paupers, and rarely find themselves comfortable with the rest of society. Then again, they were like that before this event too.
There's things you can do that you can't take back, your first break through psychedelic tripp, loosing your virginity, having a baby, initiating into a religion, giving up everything you feel comfortable with to a giant pyre and hitting the road. There is a good chance that a dose of mushrooms is going to be one of those events.