Intervention: Psilocybin
Trial phase: Phase 1 | Phase 2
SMILES: CN(C)CCc1c[nH]c2cccc(OP(=O)(O)O)c12
Sex: All
Age groups: Adult
Healthy volunteers: Accepts Healthy Volunteers
Participants at risk: 13
Group description: Participants will be administered a 25 mg/70 kg dose of psilocybin

Psilocybin: 25 mg/70 kg Psilocybin
Eligibility criteria:
Inclusion Criteria:

Have given written informed consent
Have at least a high-school level of education or equivalent, and be fluent in English
Be healthy and psychologically stable as determined by screening for medical and psychiatric problems via a personal interview, a medical questionnaire, a physical examination, an electrocardiogram (ECG), and routine medical blood and urinalysis laboratory tests
Agree to consume approximately the same amount of caffeine-containing beverage (e.g., coffee, tea) that he/she consumes on a usual morning, before arriving at the research unit on the morning of the drug session day. If the participant does not routinely consume caffeinated beverages, he/she must agree not to do so on the session day.
Agree to refrain from using any psychoactive drugs, including alcoholic beverages and nicotine, within 24 hours of each drug administration. The exception is caffeine.
Agree not to take any "as needed" medications on the mornings of drug sessions
Agree not to take sildenafil (Viagra®), tadalafil, or similar medications within 72 hours of each drug administration.
Agree that for one week before each drug session, he/she will refrain from taking any nonprescription medication, nutritional supplement, or herbal supplement except when approved by the study investigators. Exceptions will be evaluated by the study investigators and will include acetaminophen, non-steroidal anti-inflammatory drugs, and common doses of vitamins and minerals.
Have limited lifetime use of hallucinogens

Exclusion Criteria:

Women who are pregnant (as indicated by a positive urine pregnancy test assessed at intake and before each drug session) or nursing; women who are of child-bearing potential and sexually active who are not practicing an effective means of birth control.
Cardiovascular conditions: coronary artery disease, stroke, angina, uncontrolled hypertension, a clinically significant ECG abnormality (e.g., atrial fibrilation), artificial heart valve, or stroke in the past year
Epilepsy with history of seizures
Insulin-dependent diabetes; if taking oral hypoglycemic agent, then no history of hypoglycemia
Currently taking psychoactive prescription medication on a regular (e.g., daily) basis
Currently taking on a regular (e.g., daily) basis any medications having a primary centrally-acting serotonergic effect, including mono-amine oxidase inhibitors (MAOIs). For individuals who have intermittent or "as needed" use of such medications, psilocybin sessions will not be conducted until at least 5 half-lives of the agent have elapsed after the last dose.
More than 20% outside the upper or lower range of ideal body weight according to Metropolitan Life height and weight table
Current or past history of meeting Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) criteria for schizophrenia spectrum or other psychotic disorders (except substance/medication-induced or due to another medical condition), or Bipolar I or II Disorder
Current or past history within the last 5 years of meeting DSM-5 criteria for a moderate or severe alcohol or drug use disorder (excluding caffeine and nicotine)
Have a first or second-degree relative with schizophrenia spectrum or other psychotic disorders (except substance/medication-induced or due to another medical condition), or Bipolar I or II Disorder
Has a psychiatric condition judged to be incompatible with establishment of rapport or safe exposure to psilocybin
Head trauma
Claustrophobia incompatible with scanning
Cardiac pacemaker
Implanted cardiac defibrillator
Aneurysm brain clip
Inner ear implant
Prior history as a metal worker and/or certain metallic objects in the body -- must complete magnetic resonance imaging (MRI) screening form and be approved by MRI technologist before each scan