A commentary notes that in the past 6 years, there have been revolutionary changes in the nosology of insomnia in two major diagnostic classifications: the DSM-51 and the International Classification of Sleep Disorders, Third Edition (ICSD-3). The distinction between so-called primary and secondary insomnia has been abandoned, and the previous position that defined insomnia as a symptom has been altered to recognise insomnia disorder as a separate disease. It suggests that “this new subtyping approach might add a new page to the history of the insomnia nosology, promoting discoveries of new mechanisms and different interventions.”