title: Behavior change techniques in popular alcohol reduction apps: content analysis.
abstract: BACKGROUND
  Mobile phone apps have the potential to reduce excessive alcohol consumption cost-effectively. Although hundreds of alcohol-related apps are available, there is little information about the behavior change techniques (BCTs) they contain, or the extent to which they are based on evidence or theory and how this relates to their popularity and user ratings.
  
  
  OBJECTIVE
  Our aim was to assess the proportion of popular alcohol-related apps available in the United Kingdom that focus on alcohol reduction, identify the BCTs they contain, and explore whether BCTs or the mention of theory or evidence is associated with app popularity and user ratings.
  
  
  METHODS
  We searched the iTunes and Google Play stores with the terms "alcohol" and "drink", and the first 800 results were classified into alcohol reduction, entertainment, or blood alcohol content measurement. Of those classified as alcohol reduction, all free apps and the top 10 paid apps were coded for BCTs and for reference to evidence or theory. Measures of popularity and user ratings were extracted.
  
  
  RESULTS
  Of the 800 apps identified, 662 were unique. Of these, 13.7% (91/662) were classified as alcohol reduction (95% CI 11.3-16.6), 53.9% (357/662) entertainment (95% CI 50.1-57.7), 18.9% (125/662) blood alcohol content measurement (95% CI 16.1-22.0) and 13.4% (89/662) other (95% CI 11.1-16.3). The 51 free alcohol reduction apps and the top 10 paid apps contained a mean of 3.6 BCTs (SD 3.4), with approximately 12% (7/61) not including any BCTs. The BCTs used most often were "facilitate self-recording" (54%, 33/61), "provide information on consequences of excessive alcohol use and drinking cessation" (43%, 26/61), "provide feedback on performance" (41%, 25/61), "give options for additional and later support" (25%, 15/61) and "offer/direct towards appropriate written materials" (23%, 14/61). These apps also rarely included any of the 22 BCTs frequently used in other health behavior change interventions (mean 2.46, SD 2.06). Evidence was mentioned by 16.4% of apps, and theory was not mentioned by any app. Multivariable regression showed that apps including advice on environmental restructuring were associated with lower user ratings (Β=-46.61, P=.04, 95% CI -91.77 to -1.45) and that both the techniques of "advise on/facilitate the use of social support" (Β=2549.21, P=.04, 95% CI 96.75-5001.67) and the mention of evidence (Β=1376.74, P=.02, 95%, CI 208.62-2544.86) were associated with the popularity of the app.
  
  
  CONCLUSIONS
  Only a minority of alcohol-related apps promoted health while the majority implicitly or explicitly promoted the use of alcohol. Alcohol-related apps that promoted health contained few BCTs and none referred to theory. The mention of evidence was associated with more popular apps, but popularity and user ratings were only weakly associated with the BCT content.
authors.affiliation: Department of Clinical, Educational and Health Psychology, University College London, London, United Kingdom. david.crane.13@ucl.ac.uk.
authors.forename: David
authors.identifier: http://orcid.org/0000-0002-9755-0214
authors.initials: D
authors.lastname: Crane
authors.forename: Claire
authors.identifier: http://orcid.org/0000-0002-6589-299X
authors.initials: C
authors.lastname: Garnett
authors.forename: James
authors.identifier: http://orcid.org/0000-0002-2797-5428
authors.initials: J
authors.lastname: Brown
authors.forename: Robert
authors.identifier: http://orcid.org/0000-0002-0291-5760
authors.initials: R
authors.lastname: West
authors.forename: Susan
authors.identifier: http://orcid.org/0000-0003-0063-6378
authors.initials: S
authors.lastname: Michie
mesh_terms: D000428:Alcohol Drinking; D001521:Behavior Therapy; D040421:Cell Phone; D015438:Health Behavior; D006801:Humans; D008297:Male; D063731:Mobile Applications; D017216:Telemedicine / Q000379:methods*
keywords: alcohol; android; apps; behaviour change; digital; iPhone; intervention; mHealth; smartphone