StressMOR-SAFENCT07778511
How Does the Opioid System Shape Stress and Social Behaviour in Men and Women and What Role Does Childhood Unpredictability Play?
A study testing Morphine in people with Stress and Early Life Stress, run by Sara L. Kroll at 1 site in Switzerland.
Trial summary
The study aims to investigate sex differences in the effect of mu-opioid receptor (MOR) activation on stress response and social behaviour modulated by early life stress. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Stress, Early Life Stress, Sex Differences
- What is being tested?
- Morphine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 72 participants
- Where
- 1 siteSwitzerland
- Study dates
- 24 Sep 2026to Mar 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age 18-40 years
- Ability to read, understand, and provide written informed consent in German
- Proficiency in German
- Able to give blood samples (no blood- or needle-related phobia)
- Good health as determined by medical history, ECG, and clinical assessment of lab tests. Lab tests will include potassium, creatinine, hemoglobin, glucose, calcium, BUN, complete blood count, total bilirubin, AST, ALT, and GGT. The final decision will be according to the judgment of the study physician.
- Females must have a negative urine pregnancy test (hCG) at inclusion and at the start of each study session. Females of childbearing potential who are sexually active and have not been surgically sterilized must agree to use an adequate method of birth control during the study.
- Prior experience with medical opioids (at least one experience with prescription opioids such as oxycodone, morphine, hydromorphone, fentanyl, hydrocodone, codeine, or dihydrocodeine) and paracetamol.
- Body mass index (BMI) between 19 and 30 kg/m2
Who cannot join
- Any current instable medical or neurological condition
- Any clinically significant psychiatric disorder (i.e., psychotic and stress-related disorders) including a diagnosis of substance use disorder (defined in DSM-5 terms as Moderate or Severe). Participants will be screened using the Structured Clinical Interview - SCID for DSM-5). If indication is obtained that a clinically significant psychiatric disorder may be present, a full SCID will be carried out by appropriately trained staff.
- Significant adverse reaction to prior opioid or paracetamol exposure
- Reporting any illegal drug use >15 life-time occasions and regular drug use during the last three months incl. the test period (except for nicotine and alcohol)
- Any current use of CNS-active medications.
- Current use of opioid analgesics, opioid use for > 6 weeks (lifetime), or within the three months prior to study enrollment.
Show all 22Show fewer
- Fagerström Test of Nicotine Dependence (FTND) Score > 5 (strong nicotine dependence)
- Heavy alcohol use based on the Alcohol Use Disorder Identification Test (AUDIT)
- Lifetime diagnosis of cardiac disease.
- Clinically significant laboratory or ECG abnormality that could be a safety issue in the study
- Acute or chronic respiratory issues (e.g., cold, flu, asthma, etc.)
- Lifetime diagnosis of liver or kidney disease including moderate or severe renal impairment (creatinine clearance < 50 ml/min)
- Lifetime diagnosis of schizophrenia, bipolar disorder, obsessive-compulsive disorder, or autism spectrum disorder according to DSM-5
- Diagnosis of a current episode of depression based on DSM-5 criteria
- Current diagnosis of a moderate or severe substance use disorder according to DSM-5
- Daily cannabis consumption in the past three months
- Use of psychotropic medication within the last 7 days
- Participation in other pharmacological studies within the last 2 months
- Alcohol use within the last 24 hours controlled by breathalyzer
- Unable to provide a negative urine drug screen (cannabinoids, amphetamines, opiates and opioids, benzodiazepines, and cocaine).
- Positive pregnancy test or nursing (self-report)
- For women: irregular menstrual cycle or menopause
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Switzerland1 site, 1 recruiting
- Recruiting
University Hospital of Psychiatry Zurich
Zurich, 8032
Sara L Kroll, Dr. phil., +41 (0)58 384 34 13, saraliane.kroll@bli.uzh.ch
Ella L. Sommer, +41 (0)58 384 26 01, ella.sommer@bli.uzh.ch
About this study
Official title: Randomized, Double-blind, Placebo-controlled, Crossover Study Investigating Sex-specific Effects of Mu-opioid Receptor Activation on Stress and Social Interaction and Its Modulation by Early Life Stress
The study aims to investigate sex differences in the effect of mu-opioid receptor (MOR) activation on stress response and social behaviour modulated by early life stress.
Read the detailed description
While opioid use disorder presents a rising public health concern, the underlying neurobiological mechanisms of substance use are not well understood. In animal studies, activation of the Mu Opioid Receptor (MOR) system has been shown to have stress-buffering effects and to decrease affiliative behaviour, which is in line with addiction models postulating impaired stress response and poor social interactions to be risk indicators for addiction pathogenesis. In humans however, this has not been consistently found. Importantly, behavioural pharmacology studies have often been restricted to male test subjects or have been underpowered. Therefore, a significant knowledge gap remains regarding sex-specific differences in MOR activation. The additional impact of chronic stress in the form of early life stress significantly affects brain development, in turn shaping stress reactivity and affiliative behaviour in later life. This forms the basis of the research question of the present study, whether sex and childhood unpredictability modulate the effects of MOR activation on stress response and social interaction behaviour.
The prototypical opioid morphine will be used to activate the MOR. Participants will receive the study medication on two separate visits in a randomised, counterbalanced order. Afterwards, participants will conduct computer-based stress and social interaction tasks.
Learning more about individual differences in MOR activation and its effects on stress and social behaviour can help to uncover vulnerability and risk factors for opioid use disorder and improve personalised treatment opportunities.
- Conditions
- Stress, Early Life Stress, Sex Differences, Opioid
- Being tested
- Morphine, Placebo
- Keywords
- mu opioid receptor, stress, early life stress, social behaviour, affiliative behaviour, sex differences, endocannabinoid system, morphine, opioid use disorder
- Medical subject headings
- Stress, Psychological, Social Behavior, Opioid-Related Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MorphineDrug
Sevredol 10mg, oral single-dose administration
PlaceboDrug
identical in appearance to active drug, containing no active substance (mannitol), oral one-time administration
| Study group | Role | What they receive |
|---|---|---|
| Morphine | Active comparator | Participants receive the active drug (morphine) on Visit 1or Visit 2. Receives: Drug: Morphine |
| Placebo | Placebo comparator | Participants receive the non-active comparator (placebo) on Visit 1 or Visit 2. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Self-report of subjective stress during stress exposure
Sex-specific differences in the stress relieving effects of morphine compared to placebo. Subjective stress response will be measured by differences between self- and other condition in ratings using a 1-7 Visual Analogue Scale (VAS) with the anchors "not at all" (1) to "very much" (7) for the items "How secure do you feel?" and "How stressed do you feel?" throughout the stress task.
Measured: During the experimental stress task
Endocrinological markers of stress response
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by changes in plasma concentrations of cortisol and endocannabinoids (2-AG, AEA, PEA, SEA, OEA).
Measured: Throughout the experiment sessions (baseline and approx. 10, 20, 30, 60 and 105 minutes after stress onset, 6 samples).
Psychophysiological stress response of heart rate measured by electrocardiogram
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in heart rate (beats per minute).
Measured: During the experimental stress task
Psychophysiological stress response of heart rate variability measured by electrocardiogram
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in heart rate variability.
Measured: During the experimental stress task
Psychophysiological measure of sympathetic activity
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in skin conductance response (SCR).
Measured: During the experimental stress task
Changes in self-reported subjective stress over time
Sex-specific differences in morphine-mediated stress relief measured by changes in Visual Analogue Scales (VAS), ranging from 0-100 with the anchors " not at all " (0) and "extremely" (100) for the items:
"I feel stressed", "I feel safe", "I feel relaxed", "I have a dry mouth", "I feel nauseous", "I feel confident", "I feel ashamed", "I feel vulnerable"
Measured: Throughout the experimental sessions (from before stress induction to 10, 20, 30, 60 and 105 minutes after stress onset, 7 times).
Self-reported feeling of shame post-stress
Sex-differences in morphine effects on the Experiential Shame Scale (ESS) score, ranging from 25 -100, with higher values indicating stronger feelings of shame.
Measured: ~10 minutes after stress onset
Changes in self-reported affect over time
Sex-specific differences in morphine effects on changes of positive and negative affect measured using the Positive and Negative Affect Schedule (PANAS) scores. Scores for both subscales range from 10 to 50 with higher scores indicating stronger positive or negative affect, respectively.
Measured: Throughout the experimental sessions (from before stress induction to 10, 30, 60 and 105 minutes after stress onset, 6 times).
Early life stress
Modulation of the Questionnaire of Unpredictability in Childhood (QUIC) sum score on differences in primary outcomes. Scores range from 0-38 with higher scores indicating greater exposure to instability and unpredictability during childhood.
Measured: Prior to enrollment
Secondary outcomes (21)
Subjective differences in experiencing social interaction
Sex-specific differences in morphine effects on subjective pleasantness ratings measured by VAS scales (1-100) during the social approach/avoidance task and affective touch task with higher ratings indicating more pleasantness.
Measured: During the experimental tasks
Behavioural differences of social approach and avoidance
Sex-specific differences in morphine effects on behavioural measures (measured by number of button presses) during the social approach/avoidance task.
Measured: During the experimental task
Psychophysiological cardiac markers of social interaction measured by heart rate using electrocardiogram
Sex-specific differences in morphine effects on heart rate (beats per minute) during the social approach/avoidance task and the affective touch task.
Measured: During the experimental tasks
Psychophysiological cardiac markers of social interaction measured by heart rate variability using electrocardiogram
Sex-specific differences in morphine effects on heart rate variability during the social approach/avoidance task and the affective touch task.
Measured: During the experimental tasks
Psychophysiological measure of sympathetic activity during social interaction
Sex-specific differences in morphine effects on skin conductance response (SCR) during the social approach/avoidance task and the affective touch task.
Measured: During the experimental tasks.
State anxiety over time
Sex-specific differences in morphine effects on changes in state anxiety measured by the State-Trait Anxiety Inventory (STAI) score. Scores can range from 20 -80 with higher scores indicating greater anxiety
Measured: Throughout the experimental sessions (from before stress induction to approx. 10, 30, 60, and 105 minutes after stress onset, 6 times).
Drug Effects Questionnaire (DEQ)
Sex-specific differences in drug effects will be measured using the Drug Effects Questionnaire (DEQ; subjective experiences are reported of "feeling the drug", "feeling high", "drug liking" and "disliking", and "desire to take the drug again") measured on an electronic 0-100 VAS, anchors "not at all" and "extremely".
Measured: Throughout the experimental sessions (immediately after drug administration until approx. 3 hours after study medication administration, 7 times).
Drug concentration
Differences in concentration of the study drug in blood between the two test sessions.
Measured: Throughout the experimental sessions (from 1 hour after drug administration until approx. 3 hours after study medication administration, 4 samples).
Changes in oxytocin over time
Sex-specific differences in morphine effects on oxytocin levels measured in saliva.
Measured: Throughout the experimental sessions (from before stress induction to approx. 10, 20, 30, 60 and 105 minutes after stress onset, 6 samples).
Early life stress
Modulation of the Questionnaire of Unpredictability in Childhood (QUIC) sum score on differences in secondary outcomes. Scores range from 0-38 with higher scores indicating greater exposure to instability and unpredictability during childhood.
Measured: Prior to enrollment
Hair concentrations of chronic stress markers
Modulation of tonic endocannabinoid (2-AG, AEA, OEA, PEA, SEA) and glucocorticoid (cortisol, cortisone, ACTH) concentrations in hair on primary and secondary outcomes.
Measured: At screening
Personality traits
Modulation of personality traits measured by the Neuroticism-Extraversion-Openness Five-Factor Inventory (NEO-FFI) on primary and secondary outcomes. Scores range from 0-48 per subscale. Higher scores indicate higher expression of the trait.
Measured: Single measure, during experimental session
Trait assessment of loneliness
Modulation of loneliness measured by the German version of the UCLA loneliness scale on primary and secondary outcomes. Scores can range from 20-80 with higher scores indicating greater feelings of loneliness.
Measured: Single measure, during experimental session
Rosenberg Self Esteem Scale
Modulation of self-esteem measured by the Rosenberg Self Esteem Scale (RSES) on primary and secondary outcomes. Scores range from 0 -30 with scores below 15 suggesting low self-esteem, 15 to 25 reflecting a normal or average range, and 26 to 30 indicating high self-esteem.
Measured: Single measure, during experimental session.
Brief Resilience Scale
Modulation of resilience measured by the Brief Resilience Scale (BRS) on primary and secondary outcomes. Scores range from 1-5 with a higher score indicating a better ability to bounce back after stress.
Measured: Single measure, during experimental session.
Becker Depression Inventory
Modulation of depression measured by the Becker Depression Inventory (BDI-II) on primary and secondary outcomes. Scores range from 0-63 with higher scores indicating more severe depressive symptoms.
Measured: Single measure, during experimental session.
Trait anxiety level
Modulation of anxiety measured by the State Trait Anxiety Inventory (STAI) on primary and secondary outcomes. Scores range from 20-80 per subscale, with higher scores indicating higher levels of trait anxiety.
Measured: Single measure, during experimental session.
Snaith Hamilton Anhedonia Pleasure Scale
Modulation of anhedonia measured by the Snaith Hamilton Anhedonia Pleasure Scale (SHAPS) on primary and secondary outcomes. Scores range from 0-14 with higher scores indicating less ability to feel pleasure.
Measured: Single measure, during experimental session.
Relationship Structures Questionnaire
Modulation of attachment style measured by the Experiences in Close Relationship Structures Questionnaire (ECR-RS) on primary and secondary outcomes. Two scores, one for attachment-related avoidance and the other for attachment-related anxiety, are computed for different interpersonal targets. The avoidance score can be computed by averaging items 1 - 6 and the anxiety score by averaging items 7 - 9, respectively.
Measured: Single measure, during experimental session.
Socioeconomic status ladder
Modulation of socioeconomic status (SES) measured by the MacArthur SES ladder on primary and secondary outcomes. Participants rate their perceived socioeconomic status and social standing using two ladder scales ranging from 1-10: one relative to people in Switzerland and one relative to people in their community. Higher scores indicate higher perceived socioeconomic status or social standing.
Measured: Single measure, during experimental session.
Sex hormone concentration
Modulation of baseline concentrations of steroid sex hormones (testosterone, progesterone, estradiol) in plasma on primary and secondary outcomes.
Measured: Single measure at both experimental sessions.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Aug 2026
- Study start24 Sep 2026
- Primary completionDec 2026 (estimated)
- Study completionMar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for StressStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, double-blind, placebo-controlled, crossover study
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 72 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Sara L. Kroll
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Sara L. Kroll, Psychiatric University Hospital, Zurich
- Investigators
- Sara L Kroll, Dr., Principal investigator, Psychiatric University Hospital, Zurich
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07778511
- Sponsor's protocol ID
- 2026-00586
- Other IDs
- PZ00P1_208759
- Acronym
- MOR-SAFE
- Status last verified
- Sep 2026
- First submitted
- 5 Aug 2026
- Last updated
- 28 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 28 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Randomized, Double-blind, Placebo-controlled, Crossover Study Investigating Sex-specific Effects of Mu-opioid Receptor Activation on Stress and Social Interaction and Its Modulation by Early Life Stress
- ClinicalTrials.gov ID
- NCT07778511
- Acronym / sponsor ID
- MOR-SAFE / 2026-00586
- Conditions
- Stress, Early Life Stress, Sex Differences, Opioid
- Keywords
- mu opioid receptor, stress, early life stress, social behaviour, affiliative behaviour, sex differences, endocannabinoid system, morphine
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 72 participants (estimated)
- Lead sponsor
- Sara L. KrollUniversity, hospital or other
- Study start
- 24 Sep 2026 (actual)
- Primary completion
- Dec 2026 (estimated)
- Study completion
- Mar 2028 (estimated)
- First posted
- 21 Aug 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The study aims to investigate sex differences in the effect of mu-opioid receptor (MOR) activation on stress response and social behaviour modulated by early life stress.
Detailed description
While opioid use disorder presents a rising public health concern, the underlying neurobiological mechanisms of substance use are not well understood. In animal studies, activation of the Mu Opioid Receptor (MOR) system has been shown to have stress-buffering effects and to decrease affiliative behaviour, which is in line with addiction models postulating impaired stress response and poor social interactions to be risk indicators for addiction pathogenesis. In humans however, this has not been consistently found. Importantly, behavioural pharmacology studies have often been restricted to male test subjects or have been underpowered. Therefore, a significant knowledge gap remains regarding sex-specific differences in MOR activation. The additional impact of chronic stress in the form of early life stress significantly affects brain development, in turn shaping stress reactivity and affiliative behaviour in later life. This forms the basis of the research question of the present study, whether sex and childhood unpredictability modulate the effects of MOR activation on stress response and social interaction behaviour.
The prototypical opioid morphine will be used to activate the MOR. Participants will receive the study medication on two separate visits in a randomised, counterbalanced order. Afterwards, participants will conduct computer-based stress and social interaction tasks.
Learning more about individual differences in MOR activation and its effects on stress and social behaviour can help to uncover vulnerability and risk factors for opioid use disorder and improve personalised treatment opportunities.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled, crossover study
| Arm | Type | Receives |
|---|---|---|
| Morphine | Active comparator | Drug: MorphineParticipants receive the active drug (morphine) on Visit 1or Visit 2. |
| Placebo | Placebo comparator | Drug: PlaceboParticipants receive the non-active comparator (placebo) on Visit 1 or Visit 2. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (8 listed)
- Age 18-40 years
- Ability to read, understand, and provide written informed consent in German
- Proficiency in German
- Able to give blood samples (no blood- or needle-related phobia)
- Good health as determined by medical history, ECG, and clinical assessment of lab tests. Lab tests will include potassium, creatinine, hemoglobin, glucose, calcium, BUN, complete blood count, total bilirubin, AST, ALT, and GGT. The final decision will be according to the judgment of the study physician.
Key exclusion criteria (22 listed)
- Any current instable medical or neurological condition
- Any clinically significant psychiatric disorder (i.e., psychotic and stress-related disorders) including a diagnosis of substance use disorder (defined in DSM-5 terms as Moderate or Severe). Participants will be screened using the Structured Clinical Interview - SCID for DSM-5). If indication is obtained that a clinically significant psychiatric disorder may be present, a full SCID will be carried out by appropriately trained staff.
- Significant adverse reaction to prior opioid or paracetamol exposure
- Reporting any illegal drug use >15 life-time occasions and regular drug use during the last three months incl. the test period (except for nicotine and alcohol)
- Any current use of CNS-active medications.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MorphineSevredol 10mg, oral single-dose administration | Drug | Morphine |
| Placeboidentical in appearance to active drug, containing no active substance (mannitol), oral one-time administration | Drug | Placebo |
Primary outcome
Self-report of subjective stress during stress exposure
Time frame: During the experimental stress task
Sex-specific differences in the stress relieving effects of morphine compared to placebo. Subjective stress response will be measured by differences between self- and other condition in ratings using a 1-7 Visual Analogue Scale (VAS) with the anchors "not at all" (1) to "very much" (7) for the items "How secure do you feel?" and "How stressed do you feel?" throughout the stress task.
Endocrinological markers of stress response
Time frame: Throughout the experiment sessions (baseline and approx. 10, 20, 30, 60 and 105 minutes after stress onset, 6 samples).
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by changes in plasma concentrations of cortisol and endocannabinoids (2-AG, AEA, PEA, SEA, OEA).
Psychophysiological stress response of heart rate measured by electrocardiogram
Time frame: During the experimental stress task
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in heart rate (beats per minute).
Psychophysiological stress response of heart rate variability measured by electrocardiogram
Time frame: During the experimental stress task
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in heart rate variability.
Psychophysiological measure of sympathetic activity
Time frame: During the experimental stress task
Sex-specific differences in the stress relieving effects of morphine compared to placebo measured by differences between self and other condition in skin conductance response (SCR).
Changes in self-reported subjective stress over time
Time frame: Throughout the experimental sessions (from before stress induction to 10, 20, 30, 60 and 105 minutes after stress onset, 7 times).
Sex-specific differences in morphine-mediated stress relief measured by changes in Visual Analogue Scales (VAS), ranging from 0-100 with the anchors " not at all " (0) and "extremely" (100) for the items: "I feel stressed", "I feel safe", "I feel relaxed", "I have a dry mouth", "I feel nauseous", "I feel confident", "I feel ashamed", "I feel vulnerable"
Self-reported feeling of shame post-stress
Time frame: ~10 minutes after stress onset
Sex-differences in morphine effects on the Experiential Shame Scale (ESS) score, ranging from 25 -100, with higher values indicating stronger feelings of shame.
Changes in self-reported affect over time
Time frame: Throughout the experimental sessions (from before stress induction to 10, 30, 60 and 105 minutes after stress onset, 6 times).
Sex-specific differences in morphine effects on changes of positive and negative affect measured using the Positive and Negative Affect Schedule (PANAS) scores. Scores for both subscales range from 10 to 50 with higher scores indicating stronger positive or negative affect, respectively.
Early life stress
Time frame: Prior to enrollment
Modulation of the Questionnaire of Unpredictability in Childhood (QUIC) sum score on differences in primary outcomes. Scores range from 0-38 with higher scores indicating greater exposure to instability and unpredictability during childhood.
21 secondary outcomes
Subjective differences in experiencing social interaction
Time frame: During the experimental tasks
Behavioural differences of social approach and avoidance
Time frame: During the experimental task
Psychophysiological cardiac markers of social interaction measured by heart rate using electrocardiogram
Time frame: During the experimental tasks
Psychophysiological cardiac markers of social interaction measured by heart rate variability using electrocardiogram
Time frame: During the experimental tasks
Psychophysiological measure of sympathetic activity during social interaction
Time frame: During the experimental tasks.
State anxiety over time
Time frame: Throughout the experimental sessions (from before stress induction to approx. 10, 30, 60, and 105 minutes after stress onset, 6 times).
Drug Effects Questionnaire (DEQ)
Time frame: Throughout the experimental sessions (immediately after drug administration until approx. 3 hours after study medication administration, 7 times).
Drug concentration
Time frame: Throughout the experimental sessions (from 1 hour after drug administration until approx. 3 hours after study medication administration, 4 samples).
Changes in oxytocin over time
Time frame: Throughout the experimental sessions (from before stress induction to approx. 10, 20, 30, 60 and 105 minutes after stress onset, 6 samples).
Early life stress
Time frame: Prior to enrollment
Hair concentrations of chronic stress markers
Time frame: At screening
Personality traits
Time frame: Single measure, during experimental session
Trait assessment of loneliness
Time frame: Single measure, during experimental session
Rosenberg Self Esteem Scale
Time frame: Single measure, during experimental session.
Brief Resilience Scale
Time frame: Single measure, during experimental session.
Becker Depression Inventory
Time frame: Single measure, during experimental session.
Trait anxiety level
Time frame: Single measure, during experimental session.
Snaith Hamilton Anhedonia Pleasure Scale
Time frame: Single measure, during experimental session.
Relationship Structures Questionnaire
Time frame: Single measure, during experimental session.
Socioeconomic status ladder
Time frame: Single measure, during experimental session.
Sex hormone concentration
Time frame: Single measure at both experimental sessions.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Sep 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Sara L Kroll, Dr. principal investigator
Psychiatric University Hospital, Zurich
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Morphine in people with Stress and Early Life Stress, run by Sara L. Kroll at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 8 inclusion and 22 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 28 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sara L Kroll, Dr. phil. (+41 (0)58 384 34 13, saraliane.kroll@bli.uzh.ch), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Self-report of subjective stress during stress exposure (time frame: During the experimental stress task). The study lists 9 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Sep 2026.