[1] TUFTS UNIV, SCH MED, DEPT PSYCHIAT, BOSTON, MA 02111 USA
[2] BOSTON STATE HOSP, SLEEP & DREAM LAB, BOSTON, MA 02124 USA
[3] MASSACHUSETTS MENTAL HLTH CTR, NEUROPSYCHOPHARMACOL LAB, BOSTON, MA 02115 USA
[4] HARVARD UNIV, MED SCH, DEPT PSYCHIAT, CAMBRIDGE, MA 02138 USA