Laila Rida, Konstantinos Ioannidis, Samuel R Chamberlain, Jon E Grant, Peter Hellyer, Valentina Giunchiglia, William Trender, Karla V Allebrandt, Sukhi Shergill, Steven C R Williams, Adam Hampshire
Researchers are increasingly studying cognitive and psychological constructs using automated online tools due to advantages in scalability, repeatability, accessibility and affordability. The online assessment of sleep presents a challenge, as the most popular instruments for reporting different aspects of sleep were originally designed to be deployed under supervised conditions by trained personnel. Here, we develop and validate the Comprehensive Online Sleep Monitoring Scale (COSMOS), a self-reported sleep scale optimised for online, independent administration. Using data from N = 5,815 adults, we show that COSMOS has good internal (Cronbach's α = 0.85) and convergent validity, via strong associations with established sleep scales. Poorer COSMOS sleep scores were found in participants diagnosed with mental health conditions, more frequent depression or anxiety symptoms, and higher compulsivity or neuroticism traits, demonstrating good construct validity. We propose COSMOS as a comprehensive and validated sleep assessment that is suitable for large-scale online transdiagnostic and mental health research.