[1] Johns Hopkins Univ, Sch Med, Dept Neurol, Baltimore, MD 21224 USA
[2] NIMH, Mood & Anxiety Disorders Program, New Haven, CT USA
[3] Hartford Hosp, Inst Living, New Haven, CT USA
[4] Yale Univ, Sch Med, Dept Psychiat, New Haven, CT USA
[5] NIDA, Brain Imaging Ctr, Intramural Res Program, Bethesda, MD 20892 USA
[6] Univ Calif Los Angeles, David Geffen Sch Med, Dept Psychiat & Behav Sci, Los Angeles, CA USA
[7] Univ Calif Los Angeles, David Geffen Sch Med, Dept Mol & Med Pharmacol, Los Angeles, CA USA
[8] Univ Calif Los Angeles, David Geffen Sch Med, Brain Res Inst, Los Angeles, CA USA