LSD-Perceptual-Choice-Study

NCT05976698 | Completed

• 1 other identifier: 2023-00763, pk23Sterzer
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of the study is to characterize the effects of low doses of LSD (d-lysergic acid diethylamide) on behavioral and neural indicators of feedback and feedforward signaling in perceptual decision-making.

Conditions

LSD Reaction

Keywords

neural and behavioral indicators; serotonergic system; perceptual decision-making

Outcome Measures

Primary Outcomes (2)

• Change in changepoint task

  Using the changepoint task, it is examined how explicit expectations about upcoming stimuli are derived from the perceptual history and how they influence the perceptual decision in a volatile environment. The study team utilizes an established computerized task and analysis pipeline including a behavioral modeling strategy based on Bayesian inference. The task requires participants to view a train of stimuli consisting of checkerboards presented on a half-circle gradient either more on the right or more on the left side of a fixation cross. Each checkerboard represents information about whether stimuli are currently more likely to appear on the right or left side of the screen. The participants have to indicate by button press, whether they believe the right or the left side is active. Task difficulty is fixed.

  three times (once on each of the three test days; interval between test days at least 7 days)

• Change in history bias task

  With the history bias task, the study team investigates how implicit expectations about upcoming stimuli are derived from perceptual history and how they bias perceptual discrimination. In each trial, two circular gratings will be presented concurrently on the left and right sides of a fixation cross. After complete stimulus presentation, the participants indicate by button press which of the two gratings they believe had the stronger contrast in the trial (left vs. right). Task difficulty will be adjusted individually using an online quest staircase procedure, such that participants will always perform at their 75% accuracy level.

  three times (once on each of the three test days; interval between test days at least 7 days)

Study Arms (6)

Intervention order: 10 μg LSD - 20 μg LSD - Placebo

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be 10 μg LSD - 20 μg LSD - Placebo. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: active+placebo; 2. visit: active+active, 3. visit: placebo+placebo.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Intervention order: 10 μg LSD - Placebo - 20 μg LSD

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be 10 μg LSD - Placebo - 20 μg LSD. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: active+placebo; 2. visit: placebo+placebo, 3. visit: active+active.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Intervention order: 20 μg LSD - 10 μg LSD - Placebo

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be 20 μg LSD - 10 μg LSD - Placebo. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: active+active; 2. visit: active+placebo, 3. visit: placebo+placebo.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Intervention order: 20 μg LSD - placebo - 10 μg LSD

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be 20 μg LSD -placebo - 10 μg LSD. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: active+active; 2. visit: placebo+placebo, 3. visit: active+placebo.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Intervention order: placebo - 10 μg LSD - 20 μg LSD

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be placebo - 10 μg LSD - 20 μg LSD. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: placebo+placebo; 2. visit: active+placebo, 3. visit: active+active.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Intervention order: placebo - 20 μg LSD - 10 μg LSD

EXPERIMENTAL

Each subject will participate in 3 x 5 h study sessions separated by at least 7 days. Order of drug administration will be placebo - 20 μg LSD - 10 μg LSD. Vials will contain either 10μg (Active) or 0 μg LSD (Placebo). Thus, participants will be administered two vials on each study visit. 1. visit: placebo+placebo; 2. visit: active+active, 3. visit: active+placebo.

Drug: LSD 10 μg; Drug: LSD 20 μg; Drug: Placebo

Interventions

LSD 10 μg DRUG

0.5 h after the start of each study session the participants will be administered 10 μg LSD per os in the form of vials containing 1ml 20% EtOH (ethanol).

Intervention order: 10 μg LSD - 20 μg LSD - Placebo; Intervention order: 10 μg LSD - Placebo - 20 μg LSD; Intervention order: 20 μg LSD - 10 μg LSD - Placebo; Intervention order: 20 μg LSD - placebo - 10 μg LSD; Intervention order: placebo - 10 μg LSD - 20 μg LSD; Intervention order: placebo - 20 μg LSD - 10 μg LSD

LSD 20 μg DRUG

0.5 h after the start of each study session the participants will be administered 20 μg LSD per os in the form of vials containing 1ml 20% EtOH.

Intervention order: 10 μg LSD - 20 μg LSD - Placebo; Intervention order: 10 μg LSD - Placebo - 20 μg LSD; Intervention order: 20 μg LSD - 10 μg LSD - Placebo; Intervention order: 20 μg LSD - placebo - 10 μg LSD; Intervention order: placebo - 10 μg LSD - 20 μg LSD; Intervention order: placebo - 20 μg LSD - 10 μg LSD

Placebo DRUG

0.5 h after the start of each study session the participants will be administered placebo per os in the form of vials containing 1ml 20% EtOH.

Intervention order: 10 μg LSD - 20 μg LSD - Placebo; Intervention order: 10 μg LSD - Placebo - 20 μg LSD; Intervention order: 20 μg LSD - 10 μg LSD - Placebo; Intervention order: 20 μg LSD - placebo - 10 μg LSD; Intervention order: placebo - 10 μg LSD - 20 μg LSD; Intervention order: placebo - 20 μg LSD - 10 μg LSD

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• University Hospital, Basel, Switzerland: lead
• University of Basel: collaborator
• University Psychiatric Clinics Basel: collaborator

Study Sites (1)

University Psychiatric Clinics Basel

Basel, 4002, Switzerland

Location

MeSH Terms

Interventions

Lysergic Acid Diethylamide

Intervention Hierarchy (Ancestors)

Lysergic Acid; Ergolines; Ergot Alkaloids; Alkaloids; Heterocyclic Compounds; Heterocyclic Compounds, 4 or More Rings; Heterocyclic Compounds, Fused-Ring

Study Officials

• Philipp Sterzer, Prof. Dr.

  University Psychiatric Clinics Basel

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: double-blinded
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Randomized, double-blinded, cross-over study

Study Record Dates

• First Submitted: July 24, 2023
• First Posted: August 4, 2023
• Study Start: February 26, 2024
• Primary Completion: February 25, 2025
• Study Completion: February 25, 2025
• Last Updated: March 14, 2025

Record last verified: 2025-03

Locations

CH (1)