NCT05474989

Brief Summary

Alcohol use causes more overall harm than any other drug and is the seventh leading risk factor for both deaths and disability-adjusted life years. Alcohol use disorders (AUD) are among the most common and undertreated mental disorders in developed countries. Pharmacological and psychotherapeutic treatments only show limited efficacy, and around 60% of the patients relapse in the short term after withdrawal. Lysergic acid diethylamide (LSD) was investigated in numerous clinical trials during the 1950s and 1960s. Specifically, the use of LSD in the treatment of AUD was investigated extensively. A pooled analysis of six historical clinical trials demonstrated that a single dose of LSD significantly reduced alcohol use at three and six months after LSD administration. However, these trials are limited by several factors, including the use of diagnostic standards that are no longer up to date, single, high-dose treatment regimes, missing biological assessment for alcohol use, and no consequent assessment of blinding. This trial will assess the efficacy and safety of two moderate to high doses of LSD to decrease alcohol consumption in patients with AUD. The trial has a double-blind, active placebo-controlled, randomized, parallel design and will be conducted in specialized treatment centers for addictive disorders in Switzerland. The study will include 128 patients who have undergone detoxification. Participants will be allocated to one of the two intervention arms (1:1 allocation). Each arm comprises nine study visits (no drug administration) and two study days (involving LSD administration) within 30 weeks. Patients allocated to the control intervention (active placebo group) will receive 10 µg LSD on the first study day and either 10 or 20 µg LSD on the second study day. Patients allocated to the treatment intervention will receive 150 µg LSD on the first study day and either 150 µg or 250 µg LSD on the second study day. The dose will be retained or increased depending on the patient's individual response on the first study day. Participants in the control intervention will be offered to attend an open-label LSD session (150 µg) at week 31. The open-label phase will comprise three additional visits. This trial will further compare the effectiveness of LSD-assisted therapy in both group and individual therapeutic settings. To this end, participants in both drug conditions will be randomly assigned to group or individual settings. The primary outcome is the mean of percent heavy drinking days after administration of two doses of LSD during the 12 weeks following the second administration. Secondary objectives: The second aim of this study is to explore long-term changes in the cortical thickness, white matter microstructure, resting state functional connectivity (rs-FC) and cerebral blood flow (CBF) of regions associated with addiction pathophysiology. Furthermore, we will assess alterations in depressive symptoms, anxiety, and persisting effects of LSD. We will also assess biological markers of alcohol use and several predictors for treatment-response (genetics, personality traits, blinding, expectancy, and quality of acute drug effects). Lastly, we will compare LSD treatment within a group setting with treatment within an individual setting.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
128

participants targeted

Target at P75+ for phase_2

Timeline
37mo left

Started Jan 2026

Typical duration for phase_2

Geographic Reach
1 country

2 active sites

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress8%
Jan 2026Apr 2029

First Submitted

Initial submission to the registry

July 20, 2022

Completed
6 days until next milestone

First Posted

Study publicly available on registry

July 26, 2022

Completed
3.5 years until next milestone

Study Start

First participant enrolled

January 27, 2026

Completed
2.8 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

October 31, 2028

Expected
6 months until next milestone

Study Completion

Last participant's last visit for all outcomes

April 30, 2029

Last Updated

April 29, 2026

Status Verified

April 1, 2026

Enrollment Period

2.8 years

First QC Date

July 20, 2022

Last Update Submit

April 23, 2026

Conditions

Outcome Measures

Primary Outcomes (1)

  • Percent heavy drinking days

    The primary outcome is the mean percentage of heavy drinking days after administration of two doses of LSD assessed with the alcohol timeline follow-back (TLFB) questionnaire compared between treatment groups

    Period of three months after the second administration

Secondary Outcomes (29)

  • Cortical thickness measured with MRI

    One month after the first administration, one month after second administration

  • The volume of the striatum measured with MRI

    One month after the first administration, one month after second administration

  • White matter microstructure measured with MRI

    One month after the first administration, one month after second administration

  • Days to first heavy drinking day

    One month after the first administration, one, two, and three months after the second administration

  • Days to first drinking day

    One month after the first administration, one, two, and three months after the second administration

  • +24 more secondary outcomes

Study Arms (2)

Verum

EXPERIMENTAL

Subjects in the treatment arm will receive 150 μg LSD (first session) and 150 or 250 μg LSD (second session).

Drug: LSD

Active placebo

ACTIVE COMPARATOR

Subjects in the control arm will receive 10 µg LSD at the first session and 20 µg LSD at the second session.

Drug: Active placebo

Interventions

LSDDRUG

Moderate to high dose LSD

Verum

Low dose LSD

Active placebo

Eligibility Criteria

Age25 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Age ≥ 25 years
  • Participants must meet the DSM-5 criteria for a moderate to severe alcohol use disorder and must intend to stop or decrease their drinking for at least the duration of the study
  • Participants must have underwent an alcohol detoxification within the 60 days prior to screening or, in cases where no detoxification is necessary, must have been abstinent for at least 14 days.
  • A minimum of 4 HDD within the last 30 days before detoxification or cessation of alcohol use (a HDD is defined as 5 or more standard drinks per day for a man and 4 drinks for a woman; a standard drink is defined as 12 g of alcohol)

You may not qualify if:

  • Significant alcohol withdrawal symptoms at screening
  • Participating or starting in any formal treatment for AUD from visit 1 until completion of the double-blind phase
  • Treatment with disulfiram during the study
  • Past or present diagnosis of a DSM-5 psychotic or bipolar disorder in subjects or first-degree relatives
  • Current suicidality or history of a serious suicide attempt

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (2)

University Hospital of Psychiatry, University of Basel

Basel, Switzerland

RECRUITING

University Hospital of Psychiatry, University of Bern

Bern, Switzerland

RECRUITING

MeSH Terms

Conditions

Alcoholism

Interventions

Lysergic Acid Diethylamide

Condition Hierarchy (Ancestors)

Alcohol-Related DisordersSubstance-Related DisordersChemically-Induced DisordersMental Disorders

Intervention Hierarchy (Ancestors)

Lysergic AcidErgolinesErgot AlkaloidsAlkaloidsHeterocyclic CompoundsHeterocyclic Compounds, 4 or More RingsHeterocyclic Compounds, Fused-Ring

Central Study Contacts

Felix Müller, PD Dr. med.

CONTACT

Study Design

Study Type
interventional
Phase
phase 2
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
TREATMENT
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
SPONSOR INVESTIGATOR
PI Title
Sponsor-Investigator PD Dr. med. Felix Müller MD

Study Record Dates

First Submitted

July 20, 2022

First Posted

July 26, 2022

Study Start

January 27, 2026

Primary Completion (Estimated)

October 31, 2028

Study Completion (Estimated)

April 30, 2029

Last Updated

April 29, 2026

Record last verified: 2026-04

Data Sharing

IPD Sharing
Will not share

Locations