Comparative Acute Effects of R-MDMA and S-MDMA in Healthy Participants (R-S-)

May 14, 2026 updated by: University Hospital, Basel, Switzerland
Racemic ±3,4-methylenedioxymethamphetamine (MDMA) is a psychoactive substance and prototypical empathogen acutely inducing feelings of heightened mood, empathy, trust and closeness to others. These acute subjective effects of MDMA may be helpful to assist psychotherapy and MDMA has been investigated in phase 3 trials as a possible treatment in post-traumatic stress disorder.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

MDMA is a racemic substance containing equal amounts of the enantiomers S(+)- and R(-)-MDMA. Preclinical research indicates that S-MDMA mainly releases dopamine (DA), norepinephrine (NE), serotonin (5-HT), and oxytocin while R-MDMA may act more directly on 5-HT2A receptors and release prolactin (PRL). Animal studies also indicate that the two enantiomers act synergistically to produce the subjective effects of MDMA and that S-MDMA is mainly responsible for psychostimulation while R-MDMA may have fewer adverse effects and have greater prosocial effects. A human study conducted between 10/2022 and 01/2024 by our team compared the effects of R-MDMA, S-MDMA, and racemic MDMA revealing that both enantiomers have generally similar effects. However, the study did not administer equivalent doses of R- and S-MDMA. In the present study a single dose of R-MDMA and a single dose of S-MDMA, now adjusted and presumed to be equivalent, will be compared.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
26

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • Switzerland
    • Canton of Basel-City
      • Basel, Canton of Basel-City, Switzerland, 4031
        • University Hospital Basel

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Age between 18 and 65 years
  2. Good understanding of the German language
  3. Understanding of procedures and risks associated with the study
  4. Willing to adhere to the protocol and signing of the consent form
  5. Willing to refrain from the consumption of illicit psychoactive substances during the study
  6. Willing not to operate heavy machinery within 48 h after administration of a study substance (including driving a car)
  7. Willing to use effective birth-control throughout study participation.
  8. Body mass index 18 - 34.9 kg/m2

Exclusion Criteria:

  1. Relevant chronic or acute medical condition
  2. Current or previous major psychiatric disorder (e.g. bipolar disorder, schizophrenia), current depression or anxiety disorder
  3. Psychotic disorder or bipolar disorder in first-degree relatives
  4. Hypertension (SBP>140/90 mmHg) or hypotension (SBP<85 mmHg)
  5. Illicit substance use (not including cannabis) more than 20 times or any time within the previous month.
  6. Pregnancy or current breastfeeding
  7. Participation in another clinical trial (currently or within the last 30 days)
  8. Use of medications that may interfere with the effects of the study medication
  9. Tobacco smoking (>10 cigarettes/day).
  10. Excessive consumption of alcoholic beverages (>15 drinks/week)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Placebo
Other: Placebo
Placebo (Mannitol)
Experimental: 300mg R-MDMA
R-MDMA (300mg)
Drug: R-3,4-methylenedioxymethamphetamine
A dose of 300mg enantiomeric R-MDMA will be administered.
Other Names:
  • R-MDMA
Experimental: 100mg S-MDMA
S-MDMA (100mg)
Drug: S-3,4-methylenedioxymethamphetamine
A dose of 100mg enantiomeric S-MDMA will be administered.
Other Names:
  • S-MDMA

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Subjective effects
Time Frame: through study completion, an average of 18 months.
Any drug effect on the Visual Analog Scales (VAS) assessing the intensity and duration of the subjective effect on a scale from 0 - 100 percent with higher scores representing more intense effects 14 times each study day.
through study completion, an average of 18 months.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
NEO-Five-Factor-Inventory (NEO-FFI)
Time Frame: Baseline
The NEO-FFI is a self-description questionnaire with 60 items for the measurement of the "big five": neuroticism, extraversion, openness, agreeableness, and consciousness. It uses a 5-point Likert scale ranging from "completely disagree" to "fully agree".
Baseline
Freiburger Personality Inventory (FPI-R)
Time Frame: Baseline
The FPI-R version comprises 138 items and covers 12 dimensions of personality: life satisfaction, social orientation, performance orientation, inhibition, excitability, aggressiveness, stress, physical complaints, health concerns, openness, as well as the secondary factors according to Eysenck's Extraversion and Emotionality (Neuroticism). It uses a 2-point scale ("true" and "not true").
Baseline
Autonomic effects I
Time Frame: Through study completion, an average of 18 months.
Blood pressure (systolic and diastolic) will be measured with an automatic oscillometric device 14 times each study day.
Through study completion, an average of 18 months.
Autonomic effects II
Time Frame: Through study completion, an average of 18 months.
Heart rate will be measured with an automatic oscillometric device. Assessed 14 times on each study day.
Through study completion, an average of 18 months.
Autonomic effects III
Time Frame: through study completion, an average of 18 months.
Body temperature will be measured with an ear thermometer. Assessed 14 times each study day.
through study completion, an average of 18 months.
Plasma levels of oxytocin
Time Frame: Through study completion, an average of 18 months.
Assessed 3 times on each study day
Through study completion, an average of 18 months.
Plasma levels of cortisol
Time Frame: Through study completion, an average of 18 months.
Assessed 3 times on each study day
Through study completion, an average of 18 months.
Plasma levels of prolactin
Time Frame: Through study completion, an average of 18 months.
Assessed 3 times on each study day
Through study completion, an average of 18 months.
Plasma levels of R-MDMA
Time Frame: Through study completion, an average of 18 months.
Assessed 13 times on each study day
Through study completion, an average of 18 months.
Plasma levels of S-MDMA
Time Frame: Through study completion, an average of 18 months.
Assessed 13 times on each study day
Through study completion, an average of 18 months.
Additional subjective effects I
Time Frame: Through study completion, an average of 18 months.
Visual Analog Scales (VAS) assessing the intensity and duration of subjective effects on a scale from 0 - 100 percent with higher scores representing more intense effects. Assessed 14 times on each study day
Through study completion, an average of 18 months.
Additional subjective effects II
Time Frame: Through study completion, an average of 18 months.
Adjective Mood Rating Scale (AMRS) assesses the occurrence and intensity of 60 moods on a 4-point Likert scale ranging from "not at all" to "extremely" assessed 4 times on each study day
Through study completion, an average of 18 months.
Additional subjective effects III
Time Frame: Through study completion, an average of 18 months.
This world connectogen scale (TWCS) assessing the connectogenic properties of MDMA as a strong sense of connection with the here-and-now, the body, the world and spiritual principles. Assessed once each study day
Through study completion, an average of 18 months.
Saarbrücken Personality Questionnaire (SPF)
Time Frame: Baseline
Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The Saarbrücker Persönlichkeitsfragebogen (SPF) defines empathy as the "reactions of one individual to the observed experiences of another." It assesses 28-items on a 5-point Likert scale ranging from "Does not describe me well" to "Describes me very well". The measure has 4 subscales (Perspective Taking, Fantasy, Empathic Concern, Personal Distress) each made up of 7 different items.
Baseline
HEXACO personality inventory
Time Frame: Baseline
Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The HEXACO personality inventory is a six-dimensional model of human personality with 100 items.The six factors are: Honesty-Humility, Emotionality, Extraversion, Agreeableness, Conscientiousness and Openness to Experience.
Baseline
Defense Style Questionnaire (DSQ-40)
Time Frame: Baseline
Personality traits are known to affect subjective responses to psychoactive substances and are assessed for explorative future analysis of pooled data. The Defense Style Questionnaire (DSQ-40) can provide scores for 20 individual defenses, and scores for the three factors "mature", "neurotic", and "immature". Each item is evaluated on a scale from 1 to 9, where "1" indicates "completely disagree" and "9" indicates "fully agree".
Baseline
Acute adverse effects
Time Frame: Through study completion, an average of 18 months.
Assessed twice on each study day with the list of complaints (LC)
Through study completion, an average of 18 months.
Subacute adverse effects I
Time Frame: Through study completion, an average of 18 months.
The List of complains is a list of 50 symptoms assessed on a 4-point Likert scale ranging from "not at all" to "extremely". Assessed twice (24 and 72h) after each study day.
Through study completion, an average of 18 months.
Subacute adverse effects II
Time Frame: Through study completion, an average of 18 months.
The Beck Depressionindex questionnaire (BDI) is assessed once after each study day (72h) with low values indicating normal mood and high values indicating severe depression.
Through study completion, an average of 18 months.
Dose equivalence I
Time Frame: Through study completion, an average of 18 months.
5 Dimensions of Altered States of Consciousness (5D-ASC) consisting of 94 items to be rated on a visual analog scale (0-100 mm), with higher values indicating stronger effects with higher scores representing more intense effects. Assessed once on each study day
Through study completion, an average of 18 months.
Dose equivalence II
Time Frame: Through study completion, an average of 18 months.
The State of Consciousness (SCQ) Questionaire assesses the emergence and intensity of phenomenons occurring in altered states of consciousness on a 6-point Likert scale ranging from 0 ("not at all") to 5 ("extremely") once on each study day
Through study completion, an average of 18 months.
Life satisfaction and well-being I
Time Frame: Through study completion, an average of 18 months.
The Scale of positive and negative experience (SPANE) assesses 12 items of subject well-being on a 5-point-scale ranging from "very rarely" to "very often or always". Assessed once each study day and 72 h after administration.
Through study completion, an average of 18 months.
Life satisfaction and well-being II
Time Frame: Through study completion, an average of 18 months.
The "positive attitude towards life" is an 8-item subscale of the Berner Subjective Well-Being Quetsionaire for adults (BFW/E) using a six-point rating scale from "strongly disagree" (1) to "strongly agree" (6) to rate the attitude towards life. Assessed once each study day.
Through study completion, an average of 18 months.
Life satisfaction and well-being III
Time Frame: Through study completion, an average of 18 months.
The Global Life Satisfaction (GLS) assesses the overall satisfaction on a 11 point scale with 0 meaning "not at all satisfied" and 10 meaning "completely satisfied". Assessed once each study day as well as 72 h after each drug adminstration.
Through study completion, an average of 18 months.
Life satisfaction and well-being IV
Time Frame: Baseline/End of Study Visit
The Appreciation Scale (AS) includes 57 items to measure eight aspects of appreciation. Subjects are asked to rate themselves on a scale from 1 to 7 in terms of either attitude intensity ('strongly disagree' to 'strongly agree') or frequency ('never' to 'more than once a day'). Assessed at screening and end of study visit.
Baseline/End of Study Visit
Empathogenic effects I
Time Frame: Through study completion, an average of 18 months.
Multifaceted Empathy Test (MET), effects on empathy in computer tests, assessed one time during each study session.
Through study completion, an average of 18 months.
Empathogenic effects II
Time Frame: Through study completion, an average of 18 months.
Facial expression recognition test (FERT), effects on empathy in computer tests, assessed one time during each study session.
Through study completion, an average of 18 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University Hospital, Basel, Switzerland

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Matthias E Liechti, Prof. Dr. MD, University Hospital, Basel, Switzerland

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 29, 2025

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 12, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 12, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 17, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 25, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
April 1, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 15, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 14, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • BASEC 2024-01835

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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