LPD Study

Résumé de l'étude

In this study, changes in consciousness during the effects of LSD, psilocybin, and DMT are compared. LSD, psilocybin, and DMT are known as 'classic psychedelics' that trigger changes in consciousness. The substances used in this study are not approved as medications but have been used in other studies on healthy subjects and patients. So far, no study has directly compared the effects of the three substances. It is therefore unclear whether they produce different effects. However, it is known that all have different durations of action. Therefore, this study standardizes the duration of action. To do this, 3 hours after the administration of LSD, psilocybin, or DMT (or placebo), ketanserin will be administered, which will interrupt the effect. After the administration of the substances, you will be repeatedly asked to describe the experienced effect using questionnaires. Blood pressure and pulse will be measured regularly, and blood will be drawn through a venous catheter. No therapeutic effect of the substances will be investigated in this study. All appointments will take place at the University Hospital of Basel.

(BASEC)

Intervention étudiée

The study lasts at least 6 weeks and includes an entry examination of 2.5 hours, four study days of 9.5 hours each, and a final visit of 1.5 hours. The study days must be at least one week apart, but the intervals can also be longer. Appointments will be scheduled individually with you. On the four study days, you will receive

• one time LSD + 3 hours later ketanserin

• one time psilocybin + 3 hours later ketanserin

• one time DMT + 3 hours later ketanserin and

• one time placebo + 3 hours later ketanserin.

The order of the study days is randomly determined. Neither you nor your investigator knows when you will receive which substance or placebo (the study is therefore 'double-blind'). This is common in clinical studies so that knowledge of which substance it is does not influence the results. All subjects receive all substances, only in a different order.

LSD and psilocybin are administered in a drinking solution or capsules to swallow. DMT and ketanserin are administered through an intravenous venous catheter in the arm. Due to the 'blinding', you will be given a drinking solution and capsules on each study day, and a venous catheter will be placed.

The administration of ketanserin will occur 3 hours after the administration of the psychedelic substances via an already placed venous catheter. This will interrupt the psychoactive effect within half an hour.

A study day can only be conducted if you feel well and give your consent again before the start. In case of strong emotional distress, you should postpone the study day after consultation.

On the morning of each study day, two intravenous catheters will be placed in your elbows. One venous catheter will be removed after 3.5 hours, i.e., at the end of the administration of DMT (or placebo). You will be connected to the other venous catheter throughout the day. Through this, we will regularly take blood samples to examine the concentration levels of the substances in the blood. Throughout the entire study (screening, four study days, and final visit), approximately 475 ml of blood will be drawn for analysis. This corresponds to about the amount of a regular blood donation.

During the study days, we will determine the psychoactive effect of the substances using various questionnaires. One of them consists of a few simply formulated questions, so it can be filled out during the effect. Questionnaires that capture complex aspects of the experience will only be filled out after the effect has subsided. During the study day, we will also repeatedly measure pulse and blood pressure. Shortly after the administration of the substances, some measurements will be taken every 15 minutes. After that, the interval increases to 30 minutes, up to an hour in the afternoon.

You will spend the entire day in a quiet room equipped with a bed at the outpatient study center of the University Hospital of Basel. You will be supervised throughout the entire study day. About 9.5 hours after the start of the study day, you will be discharged to go home. We therefore ask you to independently arrange for someone to accompany you from the outpatient study center home at 5:30 PM. In exceptional cases, longer monitoring at the study center may be necessary (e.g., if the effect has not subsided after 8 hours).

In the days following the study day, you will also be asked for an appointment for a telephone interview. During the conversation, we will refer to a questionnaire that you fill out at the end of each study day. We conduct these interviews to generate a more accurate understanding of the effects of the test substances. The interview may last up to an hour, but you decide how thoroughly you answer the questions. To qualitatively evaluate this interview, it will be recorded on tape.

On the first of the four study days, a blood sample will also be taken for genetic testing. Genetic differences in serotonin receptors (so-called polymorphisms) may influence the effect of LSD, psilocybin, and DMT. To check this, we conduct corresponding genetic tests, during which we examine whether you have specific changes in serotonin receptors, serotonin transporters, or in the enzymes that break down or synthesize serotonin. Therefore, we do not measure your entire genome (all your genes).

(BASEC)

Maladie en cours d'investigation

Healthy subjects (basic research for understanding the human nervous system)

(BASEC)

Sponsor

Prof. Dr. med. Matthias E. Liechti

(BASEC)

Nom du comité d'éthique approbateur (pour les études multicentriques, uniquement le comité principal)

Ethikkommission Nordwest- und Zentralschweiz EKNZ

(BASEC)

Date d'approbation du comité d'éthique

12.09.2024

(BASEC)

Résultats de l'essai