An fMRI Study of Opioid-related Changes in Neural Activity

Study Overview
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Brief Summary
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The purpose of the study is to explore the effect of blocking opioids on affiliation-related neural activity.

Official Title
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An fMRI Study of Opioid-related Changes in Neural Activity

Conditions
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Social Acceptance

Intervention / Treatment
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* Drug: Naltrexone
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: naltrexone<br>single 50mg dose of naltrexone | Drug: Naltrexone<br> <br> |
| Placebo Comparator: sugar pill<br>single sugar pill | Drug: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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). | approximately one hour after taking study drug | 
| 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. | approximately two hours after taking study drug |