Effects of Mescaline and Peyote
"The long-term residual psychological and cognitive effects of mescaline, peyote’s principal active ingredient, remain poorly understood. A recent study found no evidence of psychological or cognitive deficits among Native Americans that use peyote regularly in a religious setting.2 It should be mentioned, however, that these findings may not generalize to those who repeatedly abuse the drug for recreational purposes. Peyote abusers may also experience flashbacks."
NIDA InfoFacts, "Hallucinogens: LSD, Peyote, Psilocybin, and PCP" National Institute on Drug Abuse (Bethesda, MD: National Institutes of Health, June 2009)