1 Department of Psychosocial Science, University of Bergen, Norway; Norwegian Competence Center for Sleep Disorders, Haukeland University Hospital, Norway. Electronic address: staale.pallesen@uib.no.
2 Department of Biological and Medical Psychology, University of Bergen, Norway; Elson S. Floyd College of Medicine, Washington State University, WA, USA; Sleep and Performance Center, Washington State University, WA, USA.