The article reviews current studies on the phenomenon of Internet addiction. At the moment, the problem of Internet addiction is extremely urgent, because along with the intensive development of information technologies in the world, the number of Internet users and the amount of time people spend on using the Internet resources are constantly increasing. Every year information technologies are becoming more functional for its’ their users and more widely intertwined in society, so it is regarded as an essential and integral part of people’s daily routine and a useful tool that can help to optimize almost every area of life. However, there is a growing concern among researchers who see overuse of the Internet as an addictive and pathological phenomenon that can have a number of negative effects on the physical and mental health of the user and also has a significant negative impact on the academic/work success and the social interactions with other people. Adolescents increasingly use the Internet for communication, education, entertainment, and many of the other purposes. Moreover, adolescents as the age group are considered ones of the most active users of the Internet and social media. Given this fact and their vulnerable age, they may be prone to the negative influences of the Internet overuse and Internet addiction. This article is urgent, because it reviews, analyzes, and interprets the results of empirical studies of the Internet addiction that has already been conducted in order to systemize existing information on the problem of the Internet addiction in adolescents. This article presents different approaches to the definition of the concept of “Internet addiction”. From the very beginning of research activities on the phenomena of problematic Internet use (including the Internet addiction itself and contiguous concepts of the Internet Gaming Disorder, computer addiction, and other technology based addictions), there were a number of definitions showing the contrary understandings of the causes contributing to the occurrence of the Internet addiction. Understanding of differences and interconnections between theories of the Internet addiction that are presented in this article may be helpful to compare and evaluate existing approaches and diagnostic criteria of the Internet addiction in order to have a complex understanding of the features and prerequisites of its occurrence, risk factors in adolescents, signs of the disease, and possible consequences on the health and wellbeing of the individuals.

У статті розглянуто феномен інтернет-залежності, зокрема проаналізовано підходи до визначення поняття «інтернет-залежність», діагностичні критерії інтернет-залежності, а також особливості та передумови її виникнення в осіб підліткового віку.