An Investigation of the Effects of Opioid Receptor Blockade on Changes in Self-esteem and Social Attention

Study Overview
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Brief Summary
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The purpose of this study is to explore the effects of endogenous opioids on self-esteem and attentional bias toward social cues. This is achieved by administering the drug naltrexone, which temporarily decreases endogenous opioid activity.

Official Title
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An Investigation of the Effects of Opioid Receptor Blockade on Changes in Self-esteem and Attentional Bias Toward Social Cues

Conditions
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Self Esteem

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 physical health, normal kidney and liver function results from within previous year Exclusion Criteria: allergy to naltrexone kidney or liver injury or disorder bipolar, panic, or psychotic disorders epilepsy smoking more than 15 cigarettes per day pregnancy substance abuse use of opioid analgesics, cocaine, recreational drugs (e.g., marijuana, LSD, ecstasy, etc.), or prescription medication (except oral contraceptives) within the past 10 days use of over-the-counter drugs (e.g., analgesics, anti-inflammatories, sleeping aids, etc.) or alcohol within the past 24 hours current experience of pain (e.g., headache) use of anti-diarrheal medications in the 7 days prior to the study.

Ages Eligible for Study
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Minimum Age: 18 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: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>cellulose-filled capsule | Drug: Placebo<br> <br> |
| Experimental: Naltrexone<br>single 50 mg oral dose naltrexone (capsule) | Drug: Naltrexone<br>* opioid receptor antagonist<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Self-esteem | Self-reported levels of self-esteem assessed using the Rosenberg Self-Esteem Scale (Rosenberg, 1965). Possible scores range from 1 to 4. Higher scores indicate higher levels of self-esteem. | Approximately 2 hours post placebo/drug administration | 
| Attentional bias scores for positive social cues on visual probe task | Attentional bias was assessed using a Visual Probe Task. The investigators used a version of the VPT (DeWall, Maner, & Rouby, 2009) designed to assess attentional bias to cues of social acceptance (i.e., smiles). The outcome measure was attentional bias scores, calculated by subtracting mean reaction time scores on valid trials from mean reaction time on invalid trials. Higher positive scores indicate greater attentional bias to accepting faces. | Approximately 2 hours post placebo/drug administration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Attentional bias scores for negative social cues on visual probe task | Attentional bias was assessed using a Visual Probe Task. The investigators used a version of the VPT (DeWall, Maner, & Rouby, 2009) designed to assess attentional bias to cues of social rejection (i.e., disapproving faces). The outcome measure was attentional bias scores, calculated by subtracting mean reaction time scores on valid trials from mean reaction time on invalid trials. Higher positive scores indicate greater attentional bias to disapproving faces. | Approximately 2 hours post placebo/drug administration | 
| Reaction times on neutral-neutral trials on visual probe task | Reaction times on neutral-neutral trials on the visual probe task were used to assess potential psychomotor side-effects of naltrexone | Approximately 2 hours post placebo/drug administration | 
| Self-liking | For exploratory purposes, the self-esteem measure (Rosenberg, 1965) was split into two separate subscales examining feelings of self-liking and self-competence as in Tafarodi & Milne, 2002. Self-liking is thought to be more relationally derived and based on internalized perceptions of social approval. Scores range from 1 to 4, with higher scores indicating higher levels of self-liking. | Approximately 2 hours post placebo/drug administration | 
| Self-competence | For exploratory purposes, the self-esteem measure (Rosenberg, 1965) was split into two separate subscales examining feelings of self-liking and self-competence as in Tafarodi & Milne, 2002. Self-competence is thought to be more autonomously derived and based on past goal pursuit. Scores range from 1 to 4, with higher scores indicating higher levels of self-competence. | Approximately 2 hours post placebo/drug administration |