Internet addiction is an impulse-control problem marked by an inability to inhibit Internet use, which can adversely affect a person's life, including their health and interpersonal relationships. The prevalence of Internet addiction varies among regions around the world, as shown by data from more than 89,000 individuals in 31 countries analyzed for a study published in Cyberpsychology, Behavior, and Social Networking, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. The article is available free on the Cyberpsychology, Behavior, and Social Networking website until January 18, 2015.