[1] Johns Hopkins Sch Med, Dept Psychiat & Behav Sci, Baltimore, MD USA
[2] Natl Inst Drug Abuse, Div Therapeut & Med Consequences, NIH, Bethesda, MD 20892 USA
[3] Geisel Sch Med Dartmouth, Ctr Technol & Behav Hlth, Lebanon, NH USA
[4] Univ Calif San Francisco, San Francisco Sch Med, Dept Psychiat & Behav Sci, San Francisco, CA USA
[5] Johns Hopkins Sch Med, Dept Psychiat & Behav Sci, Behav Pharmacol Res Unit, 5510 Nathan Shock Dr, Baltimore, MD 21224 USA