The Past and Future of Psychiatric Sleep Research

Sleep studies in psychiatric disorders date back to the first half of the 20th century. So far, success in establishing disease-specific sleep-related biomarkers has been quite limited. This is particularly obvious regarding insomnia, where there is no reliable correlation between subjective complaints and physiological measures of sleep. Finally, it must be acknowledged that the physiology of sleep and wakefulness and their subjective perception are essentially independent dimensions. Still, however, these dimensions are mixed up in clinical practice and research. This creates confusion, can be harmful for patients, and is identified as a major obstacle for successful psychiatric sleep research. It is proposed here that future sleep research should treat physiological sleep as a variable in psychiatric disorders which, independently of patient perception, has a transdiagnostic value, as was already proposed a decade ago by the Research Domain Criteria.