[1] Natl Inst Drug Abuse, Integrat Neurobiol Sect, Intramural Res Program, NIH, Baltimore, MD USA
[2] Harvard Med Sch, Massachusetts Gen Hosp, Dept Psychiat, Boston, MA USA
[3] Harvard Med Sch, Massachusetts Gen Hosp, Dept Neurol, Boston, MA USA
[4] Sleep Res Inst, Madrid, Spain
[5] Univ Maryland, Sch Med, Dept Psychiat, Div Addict Res & Treatment, Baltimore, MD USA
[6] Univ Maryland, Sch Med, Dept Psychiat, Subst Abuse Consultat Serv, Baltimore, MD USA
[7] Johns Hopkins Univ, Sch Med, Dept Neurol & Sleep Med, Baltimore, MD USA
[8] Natl Inst Drug Abuse, IRP, NIH, Triad Technol Bldg,333 Cassell Dr, Baltimore, MD 21224 USA