Evaluating Within-Person and Between-Person Effects Of A Personalized Normative Feedback Intervention On Drinking As They Are Moderated By Self-Determination

Study Overview
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Brief Summary
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This study evaluates within-person and between-person effects of a personalized normative feedback intervention and injunctive norms as they are altered by self-determination in heavy drinkers. Half of participants will receive personalized normative feedback and the other half will receive control feedback about media use habits.

Official Title
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Self-Determination Theory as A Framework For Evaluating Within-Person Effects Of Personalized Normative Feedback On Drinking

Conditions
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Alcohol Drinking

Intervention / Treatment
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* Behavioral: Alcohol-Specific Personalized Normative Feedback
* Behavioral: Social Media Personalized Normative Feedback


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Student at the University of Houston Above 18 years of age Heavy drinker (more than 4 drinks [women] or 5 drinks [men] on a single occasion in the last 2.5 weeks and drinks, on average, at least once per week.

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Half of participants will be randomly assigned to receive personalized normative feedback about their drinking. The other half will be randomly assigned to receive control feedback about social media use.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Alcohol-Specific Personalized Normative Feedback<br>Participants will receive feedback about their average number of days on which alcohol was consumed, average drinks per occasion, and average number of drinks per week. This feedback will include the participant's averages reported at baseline, the participant's descriptive norm of others' averages (what they think others drank), and actual others' drinking. Feedback will be about other students at their university of the same sex. | Behavioral: Alcohol-Specific Personalized Normative Feedback<br>* Participants will receive personalized normative feedback about drinking.<br>|
| Placebo Comparator: Social Media Personalized Normative Feedback<br>Participants will receive feedback about their number of hours texting, on social media websites, and playing video games. This feedback will include the participant's averages reported at baseline, the participant's descriptive norm of others' averages (what they think others did), and actual others' behavior. Feedback will be about other students at their university of the same sex. | Behavioral: Social Media Personalized Normative Feedback<br>* Participants will receive personalized normative feedback about social media use.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Between-Person Self-Determination by PNF Interaction Predicting Consumption | A structural equation model will be fit with baseline consumption, self-determination, intervention condition, and the interaction between self-determination and condition predicting follow-up alcohol consumption. Consumption will be measured with the Alcohol Consumption Index, Quantity-Frequency-Peak Alcohol Use Index, and the Daily Drinking Questionnaire. These scales will be used as indicators of a single latent consumption variable. That latent consumption measure will be the outcome of interest. | 2-4 Weeks | 
| Within-Person Self-Determination by PNF Interaction Predicting Consumption | A multilevel model will be fit with baseline consumption, daily self determination, intervention condition, and the interaction between condition and daily self-determination predicting daily alcohol consumption. Consumption will be measured as the number of drinks consumed the previous evening. | 17 Days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Between-Person Self-Determination by PNF Interaction Predicting Alcohol-Related Problems | A structural equation model will be fit with baseline consumption, alcohol-related problems, self-determination, intervention condition, and the interaction between self-determination and condition predicting follow-up alcohol-related problems. Alcohol-related problems will be measured with the Rutgers Alcohol Problems Index and the Young Adult Alcohol Consequences Questionnaire. Each of these problems measures will be split to form two indicators (for a total of four problems indicators) for an overall problems latent variable. This problems latent variable will then be used as the outcome of interest. | 2-4 Weeks | 
| Within-Person Self-Determination by PNF Interaction Predicting Alcohol-Related Problems | A multilevel model will be fit with baseline consumption, daily self determination, intervention condition, and the interaction between condition and daily self-determination predicting daily alcohol alcohol-related problems. Alcohol-related problems will be measured with a checklist of non-overlapping items from the Rutgers Alcohol Problems Index and the Young Adult Alcohol Consequences Questionnaire. This combined checklist will be used to create the overall problems outcome of interest. | 17 Days |