The Effect of LSD on Neural Synchrony, Prosocial Behavior, and Relationship Quality
- Registration Number
- NCT05670184
- Lead Sponsor
- Maastricht University
- Brief Summary
The goal of this study is to assess the effects of LSD on neural synchrony, prosocial behavior, and relationship quality in healthy romantic couples.
- Detailed Description
Evidence is growing that psychedelic substances such as psilocybin, lysergic acid diethylamide (LSD) and ayahuasca could be a potential alternative treatment option for common and difficult to treat psychiatric conditions. One proposed mechanism that psychedelics target, which is a hallmark of seemingly all psychiatric disorders, are deficits in social cognitive abilities. However, the neural underpinnings of psychedelic induced alterations in prosocial behavior are currently unknown. The investigators hypothesize psychedelics increase such prosocial behaviors by increasing neural synchrony, which is the coupling of brain-to-brain activity across two or more people; it has been found to underlie social connection and various forms of shared prosocial behavior.
The current project will primarily assess whether LSD enhances neural synchrony between romantic partners. Second, the investigators will assess whether LSD enhances prosocial behavior between members of a dyad, thus replicating previous studies which assessed prosocial behavior within one individual at a time. The investigators will also assess the relationship between neural synchrony and outcome variables of the prosocial behaviour tasks. Lastly, it will be assessed whether LSD-induced changes in neural synchrony and/or prosocial behaviour affect persisting relationship quality. Oxytocin and cytokine concentrations, will also be quantified to investigate whether there is a relationship between these factors and changes in prosocial behaviour.
The study design will be conducted according to a double-blind, placebo-controlled, 2-way crossover design. Healthy participants (N=60) who are in a relationship (N=30 couples) will receive placebo and an oral dose of 50 µg of LSD. Between each condition, there will be a minimum of 14 days washout. This leads to a total study duration of minimally four weeks, for a participant to go through the medical examination and both drug conditions.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 60
- Written Informed Consent
- Understanding the procedures and the risks associated with the study.
- Age between 18 and 35 years old.
- Being in a steady relationship for at least 6 months.
- Proficient knowledge of the English language
- Previous experience with at least one psychedelic drug (psilocybin, LSD, mescaline, Ayahuasca, DMT, 5-MeO-DMT), but not within the past 3 months
- Absence of any major medical condition as determined by medical examination and laboratory analysis
- Absence of any major psychological condition as determined by medical examination
- Free from psychotropic medication
- Participants must be willing to refrain from taking illicit psychoactive substances during the study.
- Participants must be willing to drink only alcohol-free liquids and no coffee, black or green tea, or energy drink after midnight of the evening before the study session, as well as during the study day.
- Participants must be willing not to drive a traffic vehicle or to operate machines within 24 h after substance administration.
- Normal weight, body mass index (weight/height2) between 18 and 28 kg/m2
- History of drug addiction (determined by the medical questionnaire, drug questionnaire and medical examination)
- Previous experience of serious side effects to psychedelic drugs (anxiety or panic attacks)
- Pregnancy or lactation
- Hypertension (diastolic > 90 mmHg; systolic > 140 mmHg)
- Current or history of psychiatric disorder (determined by the medical questionnaire and medical examination)
- Psychotic disorder in first-degree relatives
- Any chronic or acute medical condition
- History of cardiac dysfunctions (arrhythmia, ischemic heart disease,...)
- For women: no use of a reliable contraceptive
- Tobacco smoking (>20 per day)
- Excessive drinking (>20 alcoholic consumptions per week)
- Experience with a full dose of a psychedelic within the last three months
- Current use of SSRI medication
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Ethanol condition Ethanol 60 participants will receive placebo. LSD condition LSD 60 participants will receive LSD.
- Primary Outcome Measures
Name Time Method Neural synchrony On the acute dosing test day, 1.5-2 hours after substance administration Quantification of neural synchrony between members of a couple utilizing previously validated naturalistic interaction paradigms, including a motor cooperation task, empathy giving task, and affective touch and eye contact paradigm, will be employed. Resting state EEG will be used as a control.
- Secondary Outcome Measures
Name Time Method Self-other distinction On the acute dosing day, 2.5 hours (SMS) after substance administration. The OIS will be administered repeatedly at baseline (-0.5 hours), 2 hours, 3 hours, 4.5 hours, and 7 hours after substance administration, and at 2 days follow up. The degree of self-other merging will be assessed using synchronous multisensory stimulation (SMS), and responses on the inclusion of other in the self scale (OIS).
Prosocial behavior On the acute dosing day, 6 hours after substance administration. The PET will also be administered at 2 days follow-up. Prosocial behavior will be assessed via participants' response rate on the prosocial learning task (PLT), and the amount of effort for other individual in the prosocial effort task (PET).
Sociality On the acute dosing day, SRQ will be administered at 4.5 hours after substance administration, while the VAS-S will be administered at baseline (-0.5 hours), at 1, 2, 3, 4, 5, 6, and 7 hours after substance administration. Sociality will be measured by the social reward questionnaire (SRQ) and the visual analogue scales that measure feelings of social behavior (VAS-S).
Empathy On the acute dosing test day, 2 hours (EGT) and 3 hours (MET) after substance administration Cognitive and emotional empathy will be assessed via the empathy giving task (EGT) and the multifaceted empathy test (MET).
Trust On the acute dosing day, 6.5 hours after substance administration The trust game for couples (TGC) will assess participants' willingness to invest personal resources in pro-relationship attitudes.
Creativity On the acute dosing day, 5.5 hours (CFO, PST) after substance administration. The DAT will be administered at 2 days follow-up. Creativity will be assessed by the semantic distance in the chain free association (CFO) and the divergent association tasks (DAT), and also by the ability to separate old and new information in the pattern separation task (PST).
Social influence processing On the acute dosing day, 3 hours after substance administration Social influence processing will be assessed via participants' degree of rating adjustment after feedback in the social influence paradigm (SIP).
Conflict resolution At 2 days follow-up. The couples conflict resolution (CR) task will measure the duration of positive and negative behavior of members of a couple via video recordings of couples' interactions.
Trial Locations
- Locations (1)
Maastricht University
🇳🇱Maastricht, Netherlands