title: Differences in physical status, mental state and online behavior of people in pro-anorexia web communities.
abstract: There is a debate about the effects of pro-anorexia (colloquially referred to as pro-ana) websites. Research suggests that the effect of these websites is not straightforward. Indeed, the actual function of these sites is disputed, with studies indicating both negative and positive effects.
  
  
  
  This is the first study which systematically examined the differences between pro-anorexia web communities in four main aspects: web language used (posts); web interests/search behaviors (queries); users' self-reported weight status and weight goals; and associated self-reported mood/pathology.
  
  
  
  We collected three primary sources of data, including messages posed on three pro-ana websites, a survey completed by over 1000 participants of a pro-ana website, and the searches made on the Bing search engine of pro-anorexia users. These data were analyzed for content, reported demographics and pathology, and behavior over time.
  
  
  
  Although members of the main pro-ana website investigated appear to be depressed, with high rates of self-harm and suicide attempts, users are significantly more interested in treatment, have wishes of procreation and reported the highest goal weights among the investigated sites. In contrast, users of other pro-ana websites investigated, are more interested in morbid themes including depression, self-harm and suicide. The percentage of severely malnourished website users, in general, appears to be small (20%).
  
  
  
  Our results indicate that a new strategy is required to facilitate the communication between mental health specialists and pro-ana web users, recognizing the differences in harm associated with different websites.
authors.affiliation: Microsoft Research Israel, Israel. Electronic address: eladyt@microsoft.com.
authors.forename: Elad
authors.initials: E
authors.lastname: Yom-Tov
authors.affiliation: Department of Psychological Medicine, Schneider Children's Medical Center of Israel, Israel; School of Psychology, Interdisciplinary Center (IDC) Herzliya, Israel. Electronic address: bkanat@idc.ac.il.
authors.forename: Anat
authors.initials: A
authors.lastname: Brunstein-Klomek
authors.affiliation: Department of Psychological Medicine, Schneider Children's Medical Center of Israel, Israel. Electronic address: ariehadas@013.net.
authors.forename: Arie
authors.initials: A
authors.lastname: Hadas
authors.affiliation: School of Psychology, Interdisciplinary Center (IDC) Herzliya, Israel. Electronic address: orkeshok@gmail.com.
authors.forename: Or
authors.initials: O
authors.lastname: Tamir
authors.affiliation: Department of Psychological Medicine, Schneider Children's Medical Center of Israel, Israel; Sackler School of Medicine, Tel Aviv University, Israel. Electronic address: silvanaf@clalit.co.il.
authors.forename: Silvana
authors.initials: S
authors.lastname: Fennig
mesh_terms: D000855:Anorexia / Q000523:psychology*; D003863:Depression / Q000453:epidemiology; D005260:Female; D006801:Humans; D020407:Internet; D016015:Logistic Models; D008297:Male; D016728:Self-Injurious Behavior / Q000523:psychology*; D057545:Social Stigma; D012944:Social Support; D013405:Suicide / Q000523:psychology; D011795:Surveys and Questionnaires
keywords: Harm; Pro-anorexia; Search engines; Social networks