[1] Univ Maryland, Sch Med, Maryland Psychiat Res Ctr, Baltimore, MD 21201 USA
[2] NIDA, Chem & Drug Metab Sect, Intramural Res Program, NIH, Baltimore, MD USA
[3] Yale Univ, VA CT Healthcare Syst, New Haven, CT USA
[4] Yale Univ, Dept Psychiat, New Haven, CT 06520 USA
[5] NIDA, Magnet Resonance Imaging & Spect Sect, Intramural Res Program, Nihon Univ, Baltimore, MD USA
[6] Univ Maryland, Sch Med, VA MD Healthcare Syst, Baltimore, MD 21201 USA
[7] Univ Maryland, Sch Med, Dept Neurol, Baltimore, MD 21201 USA