Commentary on: Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance by Griffiths et al.

The study by Griffiths et al. is noteworthy both for the rigorousness of its design and execution, as well as the clarity of its results. It demonstrates that psilocybin can be safely studied in normal human beings who do not have a history of hallucinogenic drug use. As would be expected, during the psilocybin session participants showed perceptual changes and labile mood. It is striking that majority of the participants reported 2 months later that the psilocybininduced experience was personally very meaningful and spiritually significant. Indeed, most of them rated the psilocybin-induced experience as one of the top five most important experiences in their life. It is especially notable that participants reported that the drug produced positive changes in attitudes and behaviors well after the sessions, and these self-observations were consistent with ratings by friends and relatives. These participants were well-prepared for the psilocybin experience by an experienced monitor, who expressly stated that psilocybin might produce increased personal awareness and insight. However, it is clear that the effects of psilocybin were more than expectancy effects because the active drug control condition (40 mg of methylphenidate) did not produce similar effects on ratings of significance or on measures of spirituality, positive attitude, or behavior. The term psychedelic, when applied to drugs, implies that the drug experience is “mind-expanding.” The paper by Griffiths et al. illustrates the accuracy of this description for psilocybin, and I hope that this landmark paper will also be “field-expanding.” The report clearly demonstrates that we can objectively study the experiences reported by many to be profoundly spiritual and meaningful, and that we can investigate the long-term positive consequences for the individual’s attitudes and behavior. It will open the way to study the neural mechanisms responsible for these drugaltered states of consciousness. It is entirely conceivable that psychotropic agents that produce these experiences may have a role in the treatment of addictive states. Spirituality has long been a major component of the 12step approach to the treatment of alcoholism and other forms of drug addiction. Although the investigations of LSD for the treatment of alcoholism failed to show any clear-cut significant beneficial effects, the possibility that a spiritual experience, such as that reported in the present study, might be useful cannot be discounted. The set and setting in which the drug is administered may dramatically alter the drug experience. In the present study by Griffiths et al., the set was well-established for a positive experience by the preparatory sessions with the monitor, and the setting was one that was designed to produce an introspective state. This may be an important determinant of the experience and could well alter any possible therapeutic efficacy. The possibility of easing the ennui and anguish of impending death with agents such as psilocybin is also suggested in the study by Kast (1966) and those that are reviewed in the commentary of Professor Nichols. It is likely that psilocybin might have the same salutary effects. This is not an insignificant issue especially considering the large numbers of aging individuals in our society who may be in need of hospice care. In summary, I hope that this paper by Griffiths et al. renews interest in a fascinating and potentially useful class of psychotropic agents. The misuse of these substances that led to their control in Schedule I of the Controlled Substances Act cannot be allowed to continue to curtail their use as tools for understanding the neurobiology of Psychopharmacology DOI 10.1007/s00213-006-0460-x