How MOR Activation Affects Stress and Social Behavior, and How Childhood Unpredictability Modulates This in Men and Women

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

Healthy adults aged 18-40 are given morphine or placebo in a random order while completing computer-based stress and social interaction tasks. The study examines sex differences and the influence of early-life unpredictability on MOR-related stress and social outcomes. It uses a crossover design with two sessions per participant and standard safety monitoring. Outcomes focus on autonomic and behavioral responses during stress and social tasks. The aim is to better understand MOR roles in stress and social behavior to inform addiction risk mechanisms.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* 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

Exclusion Criteria:

* 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.
* 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

Where it's running

• University Hospital of Psychiatry Zurich
  Zurich, Switzerland Recruiting

Study contacts

• Principal investigator: Sara L Kroll, Dr. — Psychiatric University Hospital, Zurich
• Study coordinator: Sara L Kroll, Dr. phil.
• Email: saraliane.kroll@bli.uzh.ch
• Phone: +41 (0)58 384 34 13

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• Sex Differences in BDNF Response to a Maximal Exercise Test

  This study tests whether men and women have different levels of BDNF in the blood after a maximal exercise test.

  Recruiting McMaster University · Hamilton, Ontario · NCT07912307

• Dexmedetomidine as add-on for refractory cancer pain in palliative care

  This study tests whether adding dexmedetomidine helps improve pain control for adults with cancer in palliative care whose pain remains high despite opioids.

  Recruiting St. Olavs Hospital · Drammen and 3 other locations · NCT07885475

• Sex differences in postoperative delirium and whether family visits help

  This study looks to see if a patient’s sex changes the risk of delirium after non-cardiac surgery and whether family visits can help prevent it, especially in adults 65 and older.

  Recruiting University of Zurich · Zurich · NCT07502391

• Opioid-free versus usual discharge pain plans after major orthopedic surgery.

  This pilot trial will test whether sending adults home after major orthopedic surgery with an opioid-free pain prescription provides pain control similar to the usual opioid-containing prescription.

  Recruiting Massachusetts General Hospital · Boston, Massachusetts · NCT07265557

• Erector spinae block to lower opioid use after total abdominal hysterectomy

  This will test whether giving an erector spinae nerve block during general anesthesia can reduce opioid use for people having an elective total abdominal hysterectomy.

  Recruiting Phase 4 Kulsoom International Hospital · Islamabad, Federal · NCT07178262

• Using virtual reality to reduce opioid use after heart and thoracic operations

  This study will test whether adding virtual reality sessions after cardiac or thoracic surgery can lower opioid use in patients aged 16–40.

  Recruiting Instituto do Coracao · São Paulo, São Paulo · NCT07063394

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.