NCT06919263|Completed
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Sponsor study identifier
Secondary identifiers
OTHER_GRANT · TRDRP
interventional
1,462
1 country
1
Study Start
September 25, 2023
Actual (reported)Primary Completion
November 30, 2023
Actual (reported)Study Completion
November 30, 2023
Actual (reported)Adolescent non-users of e-cigarettes and cannabis (N = 1,462) participated in the in-class survey-based experiment. They were randomly shown 3 pairs of images featuring influencers promoting e-cigarettes alongside cannabis, (experimental group), or no-substance use or display (placebo treatment), or e-cigarette promotion alone (control). After viewing each pair of images, participants rated perceptions of influencer credibility (i.e., honesty, trustworthiness, knowledge) on the scale of 0 (e.g., dishonest) to 100 (honest). Susceptibility to use e-cigarettes was assessed after participants viewed all the images. These outcomes were then compared among participants who perceived influencers as credible and those who perceived influencers as non-credible.
Registry-reported information. Elapsed time and enrollment totals alone do not measure study progress or recruitment pace.
November 30, 2023
Actual (reported)Click on a node to explore related trials.
Some registry-reported names shown below are not yet linked in this graph.
Dates and qualifiers reported by the registry. Estimated dates do not confirm that a milestone has occurred.
September 25, 2023
Actual (reported)November 30, 2023
Actual (reported)November 30, 2023
Actual (reported)March 20, 2025
Actual (reported)April 9, 2025
Actual (reported)Perceptions of influencer credibility
Perceptions of influencer credibility (i.e., honesty, trustworthiness, knowledge) were assessed using a 0 (e.g., dishonest) -100 (e.g., honest) scale that has been validated in prior research.
assessed during the ~ 30-minute experiment, immediately after each of the three pairs of influencer images
Susceptibility to use e-cigarettes
Susceptibility to use e-cigarettes was measured using the validated three-item scale adapted from Population Assessment of Tobacco and Health (PATH), and combined into one variable (α=0.93). Consistent with prior research, the measure was dichotomized with responses "definitely not" to all items being coded as "not susceptible" and responses "probably not," "probably yes", or "definitely yes" being coded as "susceptible."
one-time assessment after the experimental exposure (immediately post-treatment)
Images featuring influencers promoting e-cigarettes alongside cannabis
Images featuring neutral profiles of influencers not using or displaying any substances
Images featuring influencers promoting e-cigarettes alone
Participants viewed survey-imbedded promotional images featuring influencers
Registry-reported names are shown in full. Names without a link have not yet been matched to a Syfrah profile.
University of Southern California
Los Angeles, California, 90032, United States
Vassey J, Chen-Sankey J, Unger JB. E-cigarette and Cannabis in Social Media Influencer Marketing and Its Effect on Adolescents: A Survey-Based Experiment. Nicotine Tob Res. 2026 Mar 24;28(4):658-667. doi: 10.1093/ntr/ntaf225.
Gina Klemm
University of Southern California
1,462 participants (actual enrollment reported by the registry).
First Submitted
March 20, 2025
First Posted
April 9, 2025
Study Start
September 25, 2023
Actual (reported)Contact the study team to confirm eligibility.
Primary Completion
November 30, 2023
Actual (reported)Study Completion
November 30, 2023
Actual (reported)Last Updated
April 9, 2025
Record last verified: 2025-03
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Source: ClinicalTrials.gov.
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