Randomised, triple-masked, two-period crossover healthy volunteer study (n=27) comparing 14-day escitalopram pretreatment versus placebo before a single oral psilocybin 25 mg session to assess subjective, physiological and gene-expression effects.
Participants undergo two study periods in randomized order: 14 days of escitalopram (10 mg x7 then 20 mg x7) or placebo pretreatment, each followed by a single 25 mg oral psilocybin session.
Primary outcome is subjective effects on consciousness measured by the 5D-ASC total score; secondary outcomes include additional psychological instruments, plasma concentrations of psilocybin and escitalopram, HTR gene expression and safety measures (autonomic effects, ECG).
Pretreatment with escitalopram (10 mg x7 days then 20 mg x7 days) followed by single-dose psilocybin 25 mg (oral) on study day.
Escitalopram 10 mg for 7 days then 20 mg for 7 days (oral) prior to psilocybin session
Psilocybin 25 mg on study day
Pretreatment with placebo (mannitol) x14 days followed by single-dose psilocybin 25 mg (oral) on study day.
Placebo (mannitol) oral capsule x14 days prior to psilocybin session
Psilocybin 25 mg on study day
This study analysed data from three clinical trials (n=79) to characterize the pharmacokinetic-pharmacodynamic relationship of orally administered psilocybin (15-30 mg). Maximal psilocin concentrations were 11 ng/ml, 17 ng/ml, and 21 ng/ml after the administration of 15, 25, and 30 mg psilocybin, respectively, and maximal levels were reached after an average of 2 hours. The duration and intensity of subjective effects were dose-dependent.