Introduction: Over the past decade, frequent use of large quantities of nitrous oxide (N2O) has become more common in the Netherlands. Although N2O poses several negative health consequences for a subgroup of problematic N2O users, there is a lack of knowledge on what characterizes these intensive users. …

Background Substance use disorders (SUDs) are prevalent in the general population, tend to follow a chronic course, are associated with many individual and social problems, and often have their onset in adolescence. However, the knowledge base from prospective population surveys and treatment-outcome …