Risks and Threats of Social Media Websites: Twitter and the Proana Movement.

In recent years, there was a spread of "proanorexia" Web sites. The aim of our study is to investigate the presence, popularity, and content of the "proana" accounts on Twitter. On January 2015, we used "Twitter Search" to retrieve the "proana" accounts. For each account, we analyzed the number of followers, tweets, and the biographical information of the users. We followed these accounts for 4 weeks, assessing the variations in followers and tweets. We also investigated the most used hashtags and the main contents of these profiles. We retrieved 341 accounts. These accounts were popular (mean followers: 2360.9, range: 5-32,700) and active (mean tweets: 4351.2, range: 5-85,700). The users were mostly girls (97.9 percent), in general teenagers (mean age: 17.9 years, range: 12-28). Only around six percent of the accounts presented a warning text about the dangerous content. Each week, we found a mean increase in both followers and tweets. The five most used hashtags resulted in descending order as follows: "thinspo," "thinspiration," "Thin15," "EDprobs," and "proana." The most commonly used contents were in the following order: autobiographic, "thinspiration" photos (inspirational photos of extremely thin girls), "thinspiration" quotes (motivational mottos), "ana tips" (advices for weight loss), and "fasting competition." We underlined a concerning high number and popularity of Twitter proanorexia groups. These accounts contain dangerous information, especially considering the young age of the users. Given the lack of warnings in almost all the accounts, a first step to control this phenomenon could be the increase of such written alerts.