The World Health Organisation (WHO) hasn't updated their International Classification of Diseases (ICD) since 1992. But now, they will be releasing the 12th edition of the ICD, and it includes something they call "Gaming Disorder". The draft document describes it as a pattern of persistent or recurrent gaming behaviour so severe that it takes "precedence over other life interests".
Many psychiatrists refer to the Diagnostic and Statistical Manual of Mental Disorders (DSM), the fifth edition of which was published in 2013. They listed that Gaming Disorder as a "condition for further study", which means that they don't officially recognise it.
A recent study from the University of Oxford suggested that, although children spend a lot of time on their screens, they generally managed to intertwine their digital pastimes with daily life. The research – looking at children aged eight to 18 – found that boys spent longer playing video games than girls.