Usability and acceptability of a mobile app to help emerging adults address their friends' substance use (Harbor): Quantitative study

Kyle Michael Bennett, Kelly Lynn Clary, Douglas Cary Smith, Carol Ann Lee

Research output: Contribution to journalArticlepeer-review


Background: Technology-assisted intervention and prevention strategies present opportunities for substance use–related research with emerging adults (EAs) and their peers. Emerging adulthood is a developmentally distinct period in which individuals between the ages of 18 and 29 years undergo unique emotional, cultural, developmental, and biological changes as they transition into adulthood. Crowdsourcing, or gathering feedback from a large group within web-based communities, offers researchers a unique and cost-effective way to obtain large amounts of information in a short period. Objective: This paper presents market feedback obtained via Amazon’s Mechanical Turk from EAs (N=458) on the acceptability and utility of brief intervention scripts for a smartphone app currently under development. The mobile app, Harbor, teaches friends of EAs with substance use problems effective and supportive strategies for helping their friend make changes in their substance use behavior. Methods: We examined feedback on the wording of the intervention scripts and estimated the market size of EAs who may use this app. Furthermore, we calculated correlations between script ratings and measures of personal risky drinking (ie, Alcohol Use Disorder Identification Test) and the participants’ use of confrontational, enabling, or supportive behaviors with an existing friend. Results: Approximately half of our sample (208/458, 45.4%) indicated that they had a close friend for whom they had concerns about their substance use, suggesting a potentially high demand for an app such as Harbor. Initial findings suggest that peers who engage in less enabling behaviors with friends who have a substance use problem exhibited lower risky drinking behaviors overall (r206=−0.501; P<.001). Concerning acceptability, 98.0% (449/458) of the sample rated the scripts’ dialogue as either somewhat, moderately, or extremely realistic (mean 3.92, SD 0.48) on 5-point Likert scale items. Finally, 95.4% (437/454) of respondents indicated that the scripts would be at least slightly helpful for training peers to help their friends with substance use issues. Finally, individuals who were better able to identify enabling language in enabling scripts self-reported fewer enabling behaviors toward their friend’s substance use (r206=−0.236; P=.001). Conclusions: There exists a demonstrated level of desirability and acceptability among EAs for a mobile app such as Harbor. EAs who wish to engage in more supportive behaviors with their friends who engage in substance use and who are amenable to assisting their friends with sobriety likely would use and benefit from this app.

Original languageEnglish (US)
Article numbere16632
JournalJournal of medical Internet research
Issue number11
StatePublished - Nov 2020


  • Community-based participatory research
  • Crowdsourcing
  • Mobile applications
  • Mobile phone
  • Peer influence
  • Substance abuse
  • Young adults

ASJC Scopus subject areas

  • Health Informatics


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