Inclusion Criteria:

• Minimum age of 21 and maximum age of 60;

• Minimum of eight years of schooling;

• Fluency in Portuguese;

• Agree, one week before the experiment, to abstain from:

  • Using any herbal supplements (except with prior approval from the researchers);
  • Using any non-prescribed medication (except non-steroidal anti-inflammatory drugs or paracetamol, provided they have prior approval from the research team);
  • Using any prescribed medication (except birth control pills, thyroid hormones, or other medications, provided they have prior approval from the research team);
  • Using recreational psychoactive substances;

• Agree to abstain, 24 hours before the experiment, from:

  • Consuming beverages with high caffeine content (e.g., coffee, mate, cola);
  • Consuming alcoholic beverages;

• Agreeing not to use caffeine or nicotine for two and six hours, respectively, after the experiment;

• Agree not to drive a motor vehicle or operate machinery for 24 hours after the experiment;

• Be available to be contacted by telephone for all planned stages;

• Agree to use effective contraception throughout the study;

• Agree to inform researchers of any medical condition or procedure that may arise prior to the experiment;

• Agree not to participate in any other interventional clinical trial for the duration of this study.

Exclusion Criteria:

• History of traumatic brain injury, stroke, epilepsy, neurological disease, or cardiovascular disease;
• Evidence or history of coronary or cerebral artery disease, peripheral vascular disease, liver disease with altered liver enzymes, or any other medical condition that the researchers, including the responsible physician, deem to significantly increase the risk of administering any substance;
• Pregnant or breastfeeding women, or women who could potentially become pregnant and are not using any effective contraceptive method;
• Women who, at the screening stage, do not have a negative pregnancy test.
• Having a history of or currently having a primary psychotic disorder, schizophrenia spectrum disorder, bipolar affective disorder (type 1 and 2), dissociative identity disorder, major depressive disorder;
• History of psychotic disorders in a first-degree relative;
• Have resting blood pressure that does not exceed 140 mmHg (systolic) and 90 mmHg (diastolic) - measured in four assessments on at least two different days;
• Have resting blood pressure below 90 mmHg (systolic) and 60 mmHg (diastolic) - measured in four assessments on at least two different days;
• Weigh less than 48 kg;
• Require therapy with psychiatric medications concurrently with the study;
• Have a history of or present with gastrointestinal disease;
• Previous use of psilocybin or similar substances;
• Frequent use (at least once a month) of any other psychoactive substance in the last year, except for nicotine, caffeine and alcohol;
• Have a history of disorders or problems related to the use of psychoactive substances;
• Not be able to provide adequate informed consent;
• Any other condition that may compromise the results or that represents any risk to the participant, according to the assessment of the research team and the responsible physician.