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

McGill University35 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Self Esteem

Interventions

NaltrexoneDRUG

opioid receptor antagonist

PlaceboDRUG

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

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.

Outcomes

Primary Outcomes

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.

Time frame: 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.

Time frame: Approximately 2 hours post placebo/drug administration

Secondary Outcomes

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.

Time frame: 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

Time frame: 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.

Data from ClinicalTrials.gov

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