LSD Occupancy of the Serotonin 2A Receptor in the Human Brain

Inclusion Criteria: • Healthy individual between 18-75 years old Exclusion Criteria: * Current or past history of primary psychiatric illness (The Diagnostic and Statistical Manual of Mental Disorders IV axis-I or World Health Organisation International Classification of Diseases-10 diagnostic classification) * Current or past history of primary psychiatric illness (The Diagnostic and Statistical Manual of Mental Disorders IV axis-I or World Health Organisation International Classification of Diseases-10 diagnostic classification) in a first degree relative (i.e., parents, siblings) * Current or past history of neurological disease, significant somatic condition/disease * Use of medication that could potentially influence results (e.g.., drugs that act on relevant components of the serotonin system or may interfere with metabolism of study drug) * Non-fluent Danish language skills * Profound visual or auditory impairments * Severe learning disability * Pregnancy on the scan date, verified by a pregnancy test (test omitted if confirmed that individual is post-menopausal) * Lactation (females) * Contraindications for magnetic resonance imaging (e.g., pacemaker, claustrophobia, etc.) * Contraindications for positron emission tomography * Alcohol or drug abuse * Allergy to administered compounds * Participant in research study with \>10 millisievert exposure within the past year or significant occupational exposure to radioactive substances * Abnormal ECG (ECG indicating curre…