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