Biological Basis of Individual Variation in Social Cooperation

What Was Tested

This registered not phased trial tested Oxytocin and Vasopressin.

The project has three overall objectives.

The first is to determine whether and how administration of intranasal oxytocin (OT) and intranasal vasopressin (AVP) influence cooperative decision-making and neural responses to cooperative and un-cooperative social interactions.

The second is to determine whether and how intranasal vasopressin influences subjective evaluations of and neural responses to same and opposite-sex face stimuli and to determine if any of these effects persist beyond the period of AVP exposure.

It had 11 arms (groups): one (experimental), one (experimental), one (placebo comparator), Within Subject Group (experimental) and Faces Task - Vasopressin (AVP) (experimental).

The registry classes the interventions as drug.

More on the Plan

There are several objective to the study.

Approximately 40 minutes later, brain function will be imaged with fMRI as participants play an iterated Prisoner's Dilemma game with same-sex partners.

The resulting data will be analyzed to investigate OT and AVP effects on cooperative behavior and the neural response to cooperative social interactions.

In addition to this cross-sectional design, a subset of participants will return on a second day for a within-subject study.

Who Took Part

707 actual participants took part.

It was open to people of any sex aged from 18 years up to 30 years.

Healthy volunteers could join, not only people with the condition.

Examples of who could join: 18-30 years of age. 21-30 for Faces component. Normal or corrected-to-normal vision of 20/40. Unmedicated depressed or anxious men between 18-22 years of age for Anxious and Depressed component.

The full record lists 4 inclusion and 20 exclusion criteria; among the exclusions: pregnancy, recent birth, or breastfeeding; history of seizures; neurological disorder.

How the Study Was Run

It was run as a randomized, factorial and triple-blind study.

Random assignment meant chance, not the researchers, decided who got Oxytocin and who got the comparison, which limits bias.

As a double-blind Oxytocin study, the assignments were hidden from both participants and investigators until the end.

Those kept unaware of assignments: participant, care provider and investigator.

It started in 2008-04 with completion listed for 2016-11.

It ran at 2 sites in United States (2).

Its stated primary purpose is basic science.

What Was Measured

The main thing measured (primary outcome): Within Subject Group: Mean Percent Signal Change in Left Caudate Nucleus in Men and Women (time frame: Visit 1 (30-75 Minutes Post-Intervention), Visit 2 (Up to 2 Weeks)).

It also tracked 12 secondary outcomes, for example Within Subject Group: Mean Difference in Number of Cooperate Choices Made by Male During the Prisoners Dilemma Game, Within Subject Group: Mean Difference in Number of Cooperate Choices Made by Female During the Prisoners Dilemma Game, Faces Task Groups: Mean Percent Signal Change in Nucleus Accumbens to Faces in Men, Faces Task Groups: Mean Percent Signal Change in Nucleus Accumbens to Faces in Women, Faces Task Groups: Mean Approachability Rating of Faces in Men and Faces Task Group: Mean Approachability Rating of Faces in Women.

What This Means in Plain Language

Put simply, this is a not phased, randomized trial of Oxytocin and Vasopressin in 707 people.

With 707 participants it is a large trial for this field.

The trial is marked completed; results are posted on the registry, and this page does not restate them.

More context: the Oxytocin compound page and the Vasopressin compound page, all human trials.