Clinical TrialHealthy VolunteersLSDActive not recruiting

LSD Occupancy of the Serotonin 2A Receptor in the Human Brain (dOccLS)

Early‑Phase interventional dose-ranging study (n=40) assessing LSD single doses (25–200 µg) to quantify 5‑HT2A receptor occupancy in healthy participants using [11C]CIMBI‑36 PET/MR.

Target Enrollment
40 participants
Study Type
Phase I interventional
Design
Non-randomized

Detailed Description

Healthy participants (18–75 years) receive a single oral dose of LSD (one of 25–200 µg) in a single‑blinded, dose‑ranging design to characterise dose–plasma–receptor occupancy relationships.

Participants undergo baseline and two post‑dose [11C]CIMBI‑36 PET scans in a simultaneous PET/MR scanner at peak and declining effects; repeated venous sampling quantifies plasma LSD and repeated subjective intensity ratings (0–10) capture acute effects.

Study Protocol

Preparation

sessions

Dosing

1 sessions

Integration

sessions

Study Arms & Interventions

LSD dose-ranging

experimental

Single-blind dose-ranging group; each participant receives one single oral dose (25–200 µg) with simultaneous PET/MR during acute effects.

Interventions

  • LSD25 - 200 µg
    via Oral• single dose• 1 doses total

    Oral D‑tartrate drinking solution (water/ethanol 20% m/m); participants single-blinded to dose (one of 25,50,75,100,125,150,175,200 µg).

Participants

Ages
18 – 75
Sexes
Male & Female

Inclusion Criteria

  • Healthy individual between 18-75 years old

Exclusion Criteria

  • Current or past history of primary psychiatric illness (DSM‑IV axis‑I or ICD‑10); current or past primary psychiatric illness in a first degree relative (parents, siblings); current or past history of neurological disease or significant somatic condition; use of medication that could influence results (e.g., drugs acting on the serotonin system or interfering with metabolism of study drug); non-fluent Danish language skills; profound visual or auditory impairments; severe learning disability; pregnancy on scan date (verified by pregnancy test; omitted if post‑menopausal); lactation (females); contraindications for MRI (e.g., pacemaker, claustrophobia); contraindications for PET; alcohol or drug abuse; allergy to administered compounds; participation in research with >10 millisievert exposure within past year or significant occupational exposure to radioactive substances; abnormal ECG or use of QT‑prolonging medication; use of psychedelic substance within preceding six months; blood donation up to three months before study (>500 ml); head injury/concussion with loss of consciousness >2 min; haemoglobin <7.8 mmol/l (women) or <8.4 mmol/l (men); ferritin outside normal range (12-300 µg/L); body-weight <50 kg or >110 kg; body-mass index >35; individual assessment deeming drug administration unsafe due to ethical or psychological circumstances

Study Details

  • Status
    Active not recruiting
  • Phase
    Phase I
  • Type
    interventional
  • Design
    Non-randomized
  • Target Enrollment40 participants
  • Timeline
    Start: 2023-11-08
    End: 2024-12-31
  • Compound
    LSD
  • Topic
    Healthy Volunteers

Locations

Neurobiology Research Unit, Rigshospitalet — Copenhagen, Denmark

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