Pharmacokinetics of Didehydro-LSD (DDH-LSD) Compared With LSD

Inclusion Criteria: 1. Age between 25 and 65 years old 2. Sufficient understanding of the German language 3. Understanding of procedures and risks associated with the study 4. Willing to adhere to the protocol and signing of the consent form 5. Willing to refrain from the consumption of illicit psychoactive substances during the study 6. Abstaining from xanthine-based liquids from the evenings prior to the study sessions and during the sessions 7. Willing not to operate heavy machinery within 48 h of substance administration 8. Willing to use effective contraceptive measures throughout study participation 9. Body mass index between 18-32 kg/m2 Exclusion Criteria: 1. Chronic or acute medical condition 2. Current or previous major psychiatric disorder 3. Psychotic disorder or bipolar disorder in first-degree relatives 4. Hypertension (SBP\>140/90 mmHg) or hypotension (SBP\<85 mmHg) 5. Use of hallucinogenic substances (not including cannabis) more than 20 times or any time within the previous two months 6. Pregnancy or currently breastfeeding 7. Participation in another clinical trial (currently or within the last 30 days) 8. Use of medication that may interfere with the effects of the study medication 9. Tobacco smoking (\>10 cigarettes/day) 10. Consumption of alcoholic beverages (\>20 drinks/week)