LSD-Perceptual-Choice-Study

Inclusion Criteria: * Willingness to adhere to the study protocol and sign the consent form * ≥ 18 and ≤ 65 years of age at Screening * Body mass index 18-29 * Fluent understanding of German * Normal or corrected-to-normal vision * Willingness to not operate a traffic vehicle or heavy machinery 24 hours after substance administration * Willingness to refrain from taking illicit psychoactive substances, including cannabis, for the duration of the study * Willingness to not consume more than one alcoholic standard drink the night before the study sessions and not consume alcohol for 24 h after each study session * Willingness to abstain from xanthine-based liquids from the evenings prior to the study sessions and during the sessions * Willingness to use effective birth-control throughout the study duration * Adequate task performance in the decision-making tasks during a practice session in the screening visit Exclusion Criteria: * Recent (\<30 days) or current participation in another clinical trial * Women that are pregnant, nursing, or planning to become pregnant during the study period * Current use of contraindicated/psychoactive medications or illicit drugs * Lifetime use of classical psychedelics more than 20 times, or any time within the previous two months * Consumption of \>5 cigarettes per day or \>20 alcoholic standard drinks per week * Severe chronic or acute medical condition * Hypertension (\>140/90 mmHg) or hypotension (\<85mmHg systolic) * Current or lifetime major mental health disorder * Personal or family (first-degree) history of a primary psychotic disorder