TY - JOUR
T1 - Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan
T2 - similarities and differences in subjective experiences
AU - Carbonaro, Theresa M.
AU - Johnson, Matthew W.
AU - Hurwitz, Ethan
AU - Griffiths, Roland R.
N1 - Publisher Copyright:
© 2017, Springer-Verlag GmbH Germany.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Rationale: Although psilocybin and dextromethorphan (DXM) are hallucinogens, they have different receptor mechanisms of action and have not been directly compared. Objective: This study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan under conditions that minimized expectancy effects. Methods: Single, acute oral doses of psilocybin (10, 20, 30 mg/70 kg), DXM (400 mg/70 kg), and placebo were administered under double-blind conditions to 20 healthy participants with histories of hallucinogen use. Instructions to participants and staff minimized expectancy effects. Various subjective, behavioral, and physiological effects were assessed after drug administration. Results: High doses of both drugs produced similar increases in participant ratings of peak overall drug effect strength, with similar times to maximal effect and time-course. Psilocybin produced orderly dose-related increases on most participant-rated subjective measures previously shown sensitive to hallucinogens. DXM produced increases on most of these same measures. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM including greater movement and more frequent, brighter, distinctive, and complex (including textured and kaleidoscopic) images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/emesis, and light-headedness. Both drugs increased systolic blood pressure, heart rate, and pupil dilation and decreased psychomotor performance and balance. Conclusions: Psilocybin and DXM produced similar profiles of subjective experiences, with psilocybin producing relatively greater visual, mystical-type, insightful, and musical experiences, and DXM producing greater disembodiment.
AB - Rationale: Although psilocybin and dextromethorphan (DXM) are hallucinogens, they have different receptor mechanisms of action and have not been directly compared. Objective: This study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan under conditions that minimized expectancy effects. Methods: Single, acute oral doses of psilocybin (10, 20, 30 mg/70 kg), DXM (400 mg/70 kg), and placebo were administered under double-blind conditions to 20 healthy participants with histories of hallucinogen use. Instructions to participants and staff minimized expectancy effects. Various subjective, behavioral, and physiological effects were assessed after drug administration. Results: High doses of both drugs produced similar increases in participant ratings of peak overall drug effect strength, with similar times to maximal effect and time-course. Psilocybin produced orderly dose-related increases on most participant-rated subjective measures previously shown sensitive to hallucinogens. DXM produced increases on most of these same measures. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM including greater movement and more frequent, brighter, distinctive, and complex (including textured and kaleidoscopic) images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/emesis, and light-headedness. Both drugs increased systolic blood pressure, heart rate, and pupil dilation and decreased psychomotor performance and balance. Conclusions: Psilocybin and DXM produced similar profiles of subjective experiences, with psilocybin producing relatively greater visual, mystical-type, insightful, and musical experiences, and DXM producing greater disembodiment.
KW - Dextromethorphan
KW - Hallucinogen
KW - Humans
KW - Insightful experience
KW - Mystical experience
KW - Psilocybin
KW - Psychedelic
KW - Subjective experience
UR - http://www.scopus.com/inward/record.url?scp=85033391118&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85033391118&partnerID=8YFLogxK
U2 - 10.1007/s00213-017-4769-4
DO - 10.1007/s00213-017-4769-4
M3 - Article
C2 - 29116367
AN - SCOPUS:85033391118
SN - 0033-3158
VL - 235
SP - 521
EP - 534
JO - Psychopharmacology
JF - Psychopharmacology
IS - 2
ER -