As the number of Internet users has increased, problems related to Internet use, including Internet addiction, have become more serious. Over the past few years, the number of smartphone users has markedly increased, and more than half of the Japanese population now possess a smartphone. A recent large-scale survey demonstrated that the majority of Internet users access the Internet via smartphone. As they are portable and multifunctional, most users have their smartphones with them throughout the day. The widespread use of social networking services (SNS), also binds smartphone users to the Internet. Taken together, a novel form of Internet addiction has emerged, i. e., smartphone addiction. In this article, the concepts and proposed diagnostic criteria of smartphone addiction are reviewed, and the results of the author's survey on smartphone addiction among Japanese college students are reported. In addition, possible interventions for smartphone users to prevent addiction are discussed.
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