Healthy
Conditions
Brief summary
Serotonin and oxytocin play a role in fear conditioning and fear extinction learning, psychological processes that are critically involved in psychiatric disorders such as posttraumatic stress disorder (PTSD). Specifically, administration of oxytocin has been shown to facilitate fear extinction in humans. Similarly, substances that release serotonin and oxytocin such as MDMA have been shown to enhance the extinction of fear memory in animals. However, there are no data on the effects of MDMA on fear extinction in humans. Therefore, the primary aim of this study is to investigate the role of acute serotonin release in the effects of fear extinction. MDMA will be used as pharmacological tool to induce serotonin release in this study.
Interventions
DRUGMDMA
125 mg MDMA per os, single dose
DRUGPlacebo
Capsules containing mannitol looking identical to the other drugs.
Sponsors
University Hospital, Basel, Switzerland
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Male * Age between 18 and 50 years. * Understanding of the German language. * Understanding the procedures and the risks associated with the study. * Participants must be willing to adhere to the protocol and sign the consent form. * 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 48 h after substance administration. * Body mass index 18-29 kg/m2.
Exclusion criteria
* Chronic or acute medical condition * Hypertension (\>140/90 mmHg) or hypotension (SBP\<85 mmHg) * Current or previous major psychiatric disorder * Psychotic disorder in first-degree relatives * Illicit substance use (with the exception of cannabis) of more than 5 times or any time within the previous month. * Participation in another clinical trial (currently or within the last 30 days) * Use of medications that may interfere with the effects of the study medications (any psychiatric medications) * Tobacco smoking (\>10 cigarettes/day) * Consumption of alcoholic standard drinks (\>10/week or \>120 g ethanol/week)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fear extinction measured by Skin conductance response | 12 months | a) Skin conductance response to conditioned stimuli |
| Fear extinction measured by Fear-potentiated startle | 12 months | b) Fear-potentiated startle to conditioned stimuli |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Autonomic effects measured by Blood pressure | 12 months | Autonomic effects measured by vital signs |
| Autonomic effects measured by Hearth rate | 12 months | Autonomic effects measured by vital signs |
| Plasma concentration of Oxytocin | 12 months | — |
| Subjective effects measured by State-trait anxiety inventory for state (STAI-S) | 12 months | — |
| Plasma concentration of MDMA | 12 months | — |
| Autonomic effects measured by Body temperature | 12 months | Autonomic effects measured by vital signs |
| Subjective effects measured by Visual analog scales | 12 months | Visual analog scales, 0-100, 0 for 'not at all' and 100 for 'extremely' |
Countries
Switzerland
Outcome results
None listed