[1] RTI Int, Res Triangle Pk, NC 27709 USA
[2] Brown Univ, Dept Psychiat & Human Behav, Providence, RI 02912 USA
[3] Butler Hosp, Providence, RI 02906 USA
[4] Massachusetts Gen Hosp, Dept Emergency Med, Boston, MA 02114 USA
[5] Harvard Med Sch, Boston, MA 02115 USA
[6] Univ Colorado, Sch Med, Dept Psychiat, Aurora, CO USA
[7] NIDA, Div Epidemiol Serv & Prevent, Bethesda, MD 20892 USA
[8] Cape Cod Hosp, Ctr Behav Hlth Serv, Hyannis, MA USA
[9] Univ Massachusetts, Med Sch, Dept Quantitat Hlth Sci, Worcester, MA 01605 USA
[10] Univ Massachusetts, Med Sch, Dept Family Med, Worcester, MA 01605 USA
[11] Univ Massachusetts, Med Sch, Dept Emergency Med, Worcester, MA 01605 USA