Randomised, double-blind, parallel study (n=75) testing varying psilocybin dose levels (very low→high) and intensity/frequency of support for spiritual practice across 2–3 sessions in healthy volunteers.
Randomised, quadruple-blind, parallel-group study assigning 75 healthy volunteers to one of five groups varying psilocybin dose levels, intensity of support for spiritual practice, and number of psilocybin sessions (2 or 3).
Psilocybin dose is double-blind with ordinal levels from very low to high; participants receive preparation with study guides and follow-up assessments including measures immediately after sessions, 3 weeks after the second psilocybin session, and 4 months after the second session (≈6 months total participation).
First of 5 groups, as described in the protocol and to which volunteers are blinded
Dose levels vary (very low to high); double-blind; participants receive 2 or 3 psilocybin sessions; at least one moderately high or high dose.
Intensity of support for spiritual practice (standard or high).
Number of sessions: assigned to 2 or 3 sessions.
Second of 5 groups, as described in the protocol and to which volunteers are blinded
Dose levels vary (very low to high); double-blind; participants receive 2 or 3 psilocybin sessions; at least one moderately high or high dose.
Intensity of support for spiritual practice (standard or high).
Number of sessions: assigned to 2 or 3 sessions.
Third of 5 groups, as described in the protocol and to which volunteers are blinded
Dose levels vary (very low to high); double-blind; participants receive 2 or 3 psilocybin sessions; at least one moderately high or high dose.
Intensity of support for spiritual practice (standard or high).
Number of sessions: assigned to 2 or 3 sessions.
Fourth of 5 groups, as described in the protocol and to which volunteers are blinded
Dose levels vary (very low to high); double-blind; participants receive 2 or 3 psilocybin sessions; at least one moderately high or high dose.
Intensity of support for spiritual practice (standard or high).
Number of sessions: assigned to 2 or 3 sessions.
Fifth of 5 groups as described in the protocol and to which volunteers are blinded
Dose levels vary (very low to high); double-blind; participants receive 2 or 3 psilocybin sessions; at least one moderately high or high dose.
Intensity of support for spiritual practice (standard or high).
Number of sessions: assigned to 2 or 3 sessions.