There are no long term physical effects from ingestion of mushrooms
containing psilocybin and psilocin. As far as long term mental effects
go this is a subject for debate and has no clear cut answer based on
the little bit of research and clinical studies that have been done.
This thread has a good conversation on this subject.
Negative long term mental effects from extended high dosages may include some cognitive impairment and HPPD
(Hallucinogen Persisting Perceptual Disorder) and possibly some
emotional liability due to effects on serotonin levels produced by the
human brain. Usually temporary, these fade with cessation of use over a
period of a few months.
Postive long term mental effects from any
dosage amount may include a personal conviction of philosophical or
religious enlightenment, a stronger sense of one's identity, and a
feeling of intimacy with all of life including nature (plants, trees,
Studies have shown that over years of
occasional use, the user notices no apparent change in his/her physical
or mental condition that would be considered detrimental. In fact, many
users state the opposite. However, it is possible, as with any
noteworthy experience in life, that if a user were to have a tough time
while under the influence of the mushroom that they could have an
ongoing spiritual or psychological issue to sort out. The odds of
somoeone having a long-term "issue," though, as a result of the
mushroom experience, is probably exceedingly rare based on all the
personal accounts we are able to read about.
"Psilocybin affects core dimensions of altered states of
consciousness and physiological parameters in a dose-dependent manner.
Our study provided no cause for concern that Psilocybin is hazardous
with respect to somatic health" - Acute psychological and
physiological effects of psilocybin in healthy humans: a double-blind,
placebo-controlled dose-effect study; Hasler F , Grimberg U, Benz MA,
Huber T, Vollenweider FX <#>
"This drug is not associated with physical
or psychological dependency, acute toxicity is largely limited to
possible panic and anxiety attacks and, in terms of chronic toxicity,
the worst that can happen are flashbacks. Consequently, the use of
paddos (hallucinogenic mushrooms) does not, on balance, present any
risk to the health of the individual" - Risk Assessment by CAM (Coordination Centre for the Assessment and Monitoring of New Drugs), 2000. <#>