Social Acceptance
Conditions
Brief summary
The purpose of the study is to explore the effect of blocking opioids on affiliation-related neural activity.
Interventions
DRUGNaltrexone
DRUGPlacebo
Sponsors
Tristen Inagaki
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
* good health * between the ages of 18 and 35, * fluent in English * right-handed (for the fMRI scan)
Exclusion criteria
* Self-reported current or past diagnoses of physical or mental illness. * Score on the Patient Health Questionnaire (depressive symptoms) above a 13 * Positive urine drug test (for Tetrahydrocannabinol (THC), Opiates, Cocaine, Amphetamine (AMP), and Methamphetamine (mAMP)) * Positive urine pregnancy test * Use of any prescription medication, except for birth control * Use of any over-the-counter medications on the day of the fMRI session and 24 hours after the fMRI session * Self-reported problems with liver functioning, including hepatitis or liver failure * Difficulty swallowing or taking pills * BMI greater than 35 or weight greater than 400 lbs * Claustrophobia * Nonremovable metal in the body
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs | approximately one hour after taking study drug | In the MRI scanner, participants read sentences written by people they knew and people they did not know in a block design. Brain activity was measured as BOLD activity in response to reading sentences from known (vs. unknown) people using functional magnetic resonance imaging (FMRI). Based on a priori hypotheses, brain activity was masked to activity in structural regions-of-interest (ROIs) of the ventral striatum (VS) and middle-insula (MI). |
| Self-reported Feelings of Connection in Response to the Scanner Tasks | approximately two hours after taking study drug | feelings of social connection in response to reading sentences from known people (i.e. average of how connected, touched, warm did you feel). Feelings were reported on a scale of 1 (not at all) to 7 (very) such that higher numbers reflect greater feelings of social connection. time frame was mistakenly entered as the start of the fMRI scan, but participants reported on their feelings of social connection after the scan. Thus, the outcome measure time frame is reported as two, rather than one, hour after taking the study drug. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Naltrexone single 50mg dose of naltrexone
Naltrexone | 40 |
| Sugar Pill single sugar pill
Placebo | 40 |
| Total | 80 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | head did not fit in fMRI scanner headres | 1 | 0 |
| Overall Study | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | Naltrexone | Sugar Pill | Total |
|---|---|---|---|
| Age, Continuous | 21.90 years STANDARD_DEVIATION 3.49 | 22.88 years STANDARD_DEVIATION 3.2 | 22.39 years STANDARD_DEVIATION 3.362 |
| Body Mass Index (BMI) | 24.30 kg/m^2 STANDARD_DEVIATION 3.6 | 23.42 kg/m^2 STANDARD_DEVIATION 2.61 | 23.86 kg/m^2 STANDARD_DEVIATION 3.15 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 10 Participants | 12 Participants | 22 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants | 2 Participants | 3 Participants |
| Race (NIH/OMB) More than one race | 2 Participants | 2 Participants | 4 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) White | 27 Participants | 23 Participants | 50 Participants |
| Sex: Female, Male Female | 27 Participants | 21 Participants | 48 Participants |
| Sex: Female, Male Male | 13 Participants | 19 Participants | 32 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 40 | 0 / 40 |
| other Total, other adverse events | 30 / 40 | 20 / 40 |
| serious Total, serious adverse events | 0 / 40 | 0 / 40 |
Outcome results
Primary
Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs
In the MRI scanner, participants read sentences written by people they knew and people they did not know in a block design. Brain activity was measured as BOLD activity in response to reading sentences from known (vs. unknown) people using functional magnetic resonance imaging (FMRI). Based on a priori hypotheses, brain activity was masked to activity in structural regions-of-interest (ROIs) of the ventral striatum (VS) and middle-insula (MI).
Time frame: approximately one hour after taking study drug
Population: all participants, 3 excluded from sugar pill group (1 for poor registration during preprocessing, 1 for technical error with task presentation, 1 for signal dropout in primary regions of interest)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Naltrexone | Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs | 0.117 BOLD signal | Standard Error 0.033 |
| Sugar Pill | Bold Oxygen-level Dependent (BOLD) Activations in Prespecified ROIs | 0.2545 BOLD signal | Standard Error 0.061 |
p-value: <0.01t-test, 1 sided
Primary
Self-reported Feelings of Connection in Response to the Scanner Tasks
feelings of social connection in response to reading sentences from known people (i.e. average of how connected, touched, warm did you feel). Feelings were reported on a scale of 1 (not at all) to 7 (very) such that higher numbers reflect greater feelings of social connection. time frame was mistakenly entered as the start of the fMRI scan, but participants reported on their feelings of social connection after the scan. Thus, the outcome measure time frame is reported as two, rather than one, hour after taking the study drug.
Time frame: approximately two hours after taking study drug
Population: All participants. Ratings from 1 participant in the naltrexone group were misplaced. 1 participant from the sugar pill group did not follow instructions and so ratings were not included in final analyses.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Naltrexone | Self-reported Feelings of Connection in Response to the Scanner Tasks | 4.576 scores on a scale | Standard Deviation 0.848 |
| Sugar Pill | Self-reported Feelings of Connection in Response to the Scanner Tasks | 4.766 scores on a scale | Standard Deviation 0.895 |
p-value: 0.338t-test, 2 sided