Sponsor was not financially able or willing to continue to support the study

The purpose of this research study is to compare an oral dose of psilocybin and an intravenous (IV) infusion of psilocybin to assess differences in how the drug is absorbed by the body, the psychedelic experience, and any side effects when taken by healthy adult participants. Participants can expect to be in the study for approximately 12 weeks.

Psilocybin, when delivered to screened and prepared participants in a controlled environment, has shown strong evidence of positive effects in treating cancer-related psychiatric distress, depression and anxiety, treatment-resistant depression, and nicotine or alcohol addiction. Psilocybin therapy is generally safe and well-tolerated when conducted under controlled conditions. Psilocybin is very rapidly transformed to the active metabolite psilocin, which is considered the active agent from psilocybin administration. Oral and IV psilocybin are expected to have similar pharmacokinetic and psychedelic effects, as well as safety profiles, while IV psilocybin will achieve more consistent blood levels than are possible with oral psilocybin.

Inclusion Criteria:

• Overall healthy and medically stable, as determined by screening
• Capable of giving signed informed consent
• Negative urine pregnancy test in persons of childbearing potential

Exclusion Criteria:

• Have any of the following cardiovascular conditions: uncontrolled hypertension, coronary artery disease, congenital long QT syndrome, cardiac hypertrophy, cardiac ischemia, congestive heart failure, prior myocardial infarction, tachycardia, artificial heart valve, corrected QT interval (QTc) >450 msec at screening, any other clinically significant screening ECG abnormality, or any other significant cardiovascular condition
• Presence of a gastrointestinal disease that could interfere with absorption of an orally administered drug
• Have epilepsy
• Positive urine drug test
• Prior adverse effects from psilocybin or other psychedelics that required hospitalization
• Currently taking on a regular basis (e.g., daily) any medications having a primary centrally acting serotonergic effect, including selective serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs), or serotonin-acting dietary supplements (such as 5-hydroxy-tryptophan or St. John's wort)
• Currently taking prohibited medications, including antihypertensive medications, UGT1A9 or 1A10 inhibitors (e.g., regorafenib, rifampicin, phenytoin, eltrombopag, mefenamic acid, diflunisal, niflumic acid, sorafenib, isavuconazole, deferasiroxor, ginseng), and aldehyde or alcohol dehydrogenase inhibitors (e.g,, disulfiram)
• Participation in another concurrent clinical study; or use of investigational drugs, biologics, or devices within 30 days prior to assignment of study drug administration order
• Anyone who is pregnant, lactating, or planning on becoming pregnant during the study
• Unwilling to withhold prohibited concomitant medications