About the Authors

Derk-Jan Dijk

d.j.dijk@surrey.ac.uk

Current address: Faculty of Health and Medical Sciences, Surrey Sleep Research Centre, University of Surrey, Guildford, United Kingdom

Affiliations Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Jeanne F. Duffy

Affiliations Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Edward J. Silva

Affiliation Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Theresa L. Shanahan

Affiliations Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Diane B. Boivin

Current address: Department of Psychiatry, Centre for Study and Treatment of Circadian Rhythms, Douglas Mental Health University Institute, McGill University, Montreal, Canada

Affiliations Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Charles A. Czeisler

Affiliations Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America, Division of Sleep Medicine, Brigham and Women's Hospital, Boston, Massachusetts, United States of America

Competing Interests

Dr. Dijk has received research funding from GSK, Eli Lilly, Merck, Ono Pharma, Philips, Airforce Office of Scientific Research, Biotechnology and the Biological Sciences Research Council and provided consulting services to Johnson and Johnson, Sanofi-aventis, Metro Naps, Pepsi Co, Actelion, Cephalon, GSK, Eli Lilly, Philips, Merck, Ono Pharma, UCB, and CHDI. Dr. Czeisler has received consulting fees/served as a paid member of scientific advisory boards for: Actelion, Ltd.; Avera Pharmaceuticals, Inc.; Bombardier Inc.; Boston Celtics; Cephalon, Inc.; Columbia River Bar Pilots; Delta Airlines; Eli Lilly and Co.; Federal Motor Carrier Safety Administration (FMCSA), U.S. Department of Transportation; Fedex Kinko's; Fusion Medical Education, LLC; Garda Síochána Inspectorate; Global Ground Support; Hypnion, Inc. (acquired by Eli Lilly and Co. in April 2007); Johnson & Johnson; Koninklijke Philips Electronics, N.V.; Minnesota Timberwolves; Morgan Stanley; Norfolk Southern; Portland Trail Blazers; Respironics, Inc.; Sanofi-Aventis Groupe; Sepracor, Inc.; Sleep Multimedia, Inc.; Sleep Research Society; Somnus Therapeutics, Inc.; Takeda Pharmaceuticals; Vanda Pharmaceuticals, Inc.; Vital Issues in Medicine; Warburg-Pincus;Zeo Inc. Dr. Czeisler owns an equity interest in Lifetrac, Inc.; Somnus Therapeutics, Inc.; Vanda Pharmaceuticals, Inc., and Zeo Inc. Dr. Czeisler received royalties from the Massachusetts Medical Society/New England Journal of Medicine; McGraw Hill, the New York Times Penguin Press and Philips Respironics. Dr. Czeisler has clinical trial research contracts from Cephalon, Inc., Merck & Co., Inc., and Pfizer, Inc.; an investigator-initiated research grant from Cephalon, Inc.; and his research laboratory at the Brigham and Women's Hospital has received unrestricted research and education funds for research expenses from Cephalon, Inc., Koninklijke Philips Electronics, N.V., ResMed, and the Brigham and Women's Hospital. Dr. Czeisler is the incumbent of an endowed professorship provided to Harvard University by Cephalon, Inc. and holds a number of process patents in the field of sleep/circadian rhythms,details of which are available on request. Since 1985, Dr. Czeisler has also served as an expert witness on various legal cases related to sleep and/or circadian rhythms. Dr. Duffy has received investigator-initiated research grants from Philips-Respironics. Dr. Boivin has received research support from Transport Canada and the Litebook Company; has participated in speaking and advisory engagements for Servier and Cephalon and is Founder/CEO of Alpha Logik Consultants, Inc. Dr. Shanahan, declares that her spouse is Dr. Czeisler. None of the commercial research grants listed in the statement relate to the current study. Our listed conflicts do not alter our adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Author Contributions

Conceived and designed the experiments: CAC JFD. Performed the experiments: DJD JFD EJS TLS. Analyzed the data: DJD EJS JFD DBB TLS. Contributed reagents/materials/analysis tools: TLS EJS. Wrote the paper: DJD JFD CAC EJS DBB TLS.