This report reviews the existing scientific evidence regarding internet-use-related addictionproblems at an individual level in Europe. In the last two decades, there has been an exponential growth in research in this field. Since 2013, internet gaming disorder has been included in the appendix of the American Psychiatric Association's fifth Diagnostic and Statistical Manual of Mental Disorders, and gaming disorder has been included in the eleventh International Classification of Diseases published by the World Health Organization. The study includes a detailed critical literature review on generalised internet addiction, online gaming, and gambling addiction in Europe. Based on scientific databases, 19 empirical studies with both community and clinical samples have been selected from Denmark, France, Germany, Greece, Italy, the Netherlands, and Spain. The majority of individuals with internet-use-related addictions were found to be educated adolescents and young males. Comorbidities with other psychiatric conditions were present as a rule, and they were more severe in the case of gaming. Cognitive behavioural therapy was the usual treatment with positive prognosis. This report provides the conceptualisation of these three internet-use-related addiction problems, together with a set of policy options, preventive actions, and evidence to support future policies in the European Union context.