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.
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)
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)
Crossover
Morphine
DrugSevredol 10mg, oral single-dose administration
Placebo
Drugidentical in appearance to active drug, containing no active substance (mannitol), oral one-time administration
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.
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).
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).
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.
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.
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.
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.
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.
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Sara L. Kroll
Lead sponsor
Psychiatric University Hospital, Zurich
Sponsor institution
