title: Pro-Anorexia and Anti-Pro-Anorexia Videos on YouTube: Sentiment Analysis of User Responses.
abstract: BACKGROUND
  Pro-anorexia communities exist online and encourage harmful weight loss and weight control practices, often through emotional content that enforces social ties within these communities. User-generated responses to videos that directly oppose pro-anorexia communities have not yet been researched in depth.
  
  
  OBJECTIVE
  The aim was to study emotional reactions to pro-anorexia and anti-pro-anorexia online content on YouTube using sentiment analysis.
  
  
  METHODS
  Using the 50 most popular YouTube pro-anorexia and anti-pro-anorexia user channels as a starting point, we gathered data on users, their videos, and their commentators. A total of 395 anorexia videos and 12,161 comments were analyzed using positive and negative sentiments and ratings submitted by the viewers of the videos. The emotional information was automatically extracted with an automatic sentiment detection tool whose reliability was tested with human coders. Ordinary least squares regression models were used to estimate the strength of sentiments. The models controlled for the number of video views and comments, number of months the video had been on YouTube, duration of the video, uploader's activity as a video commentator, and uploader's physical location by country.
  
  
  RESULTS
  The 395 videos had more than 6 million views and comments by almost 8000 users. Anti-pro-anorexia video comments expressed more positive sentiments on a scale of 1 to 5 (adjusted prediction [AP] 2.15, 95% CI 2.11-2.19) than did those of pro-anorexia videos (AP 2.02, 95% CI 1.98-2.06). Anti-pro-anorexia videos also received more likes (AP 181.02, 95% CI 155.19-206.85) than pro-anorexia videos (AP 31.22, 95% CI 31.22-37.81). Negative sentiments and video dislikes were equally distributed in responses to both pro-anorexia and anti-pro-anorexia videos.
  
  
  CONCLUSIONS
  Despite pro-anorexia content being widespread on YouTube, videos promoting help for anorexia and opposing the pro-anorexia community were more popular, gaining more positive feedback and comments than pro-anorexia videos. Thus, the anti-pro-anorexia content provided a user-generated counterforce against pro-anorexia content on YouTube. Professionals working with young people should be aware of the social media dynamics and versatility of user-generated eating disorder content online.
authors.affiliation: School of Social Sciences and Humanities, University of Tampere, Tampere, Finland. atte.oksanen@uta.fi.
authors.forename: Atte
authors.identifier: http://orcid.org/0000-0003-4143-5580
authors.initials: A
authors.lastname: Oksanen
authors.forename: David
authors.identifier: http://orcid.org/0000-0002-2820-9151
authors.initials: D
authors.lastname: Garcia
authors.forename: Anu
authors.identifier: http://orcid.org/0000-0003-2195-8114
authors.initials: A
authors.lastname: Sirola
authors.forename: Matti
authors.identifier: http://orcid.org/0000-0001-8333-9226
authors.initials: M
authors.lastname: Näsi
authors.forename: Markus
authors.identifier: http://orcid.org/0000-0002-7067-1665
authors.initials: M
authors.lastname: Kaakinen
authors.forename: Teo
authors.identifier: http://orcid.org/0000-0002-7572-9328
authors.initials: T
authors.lastname: Keipi
authors.forename: Pekka
authors.identifier: http://orcid.org/0000-0001-7472-6355
authors.initials: P
authors.lastname: Räsänen
mesh_terms: D000293:Adolescent; D000855:Anorexia / Q000523:psychology* / Q000628:therapy; D002648:Child; D005260:Female; D006801:Humans; D020407:Internet / Q000706:statistics & numerical data*; D008297:Male; D061108:Social Media / Q000706:statistics & numerical data*; D014741:Video Recording / Q000379:methods*
keywords: anorexia; eating disorders; emotions; social media