[1] VA Pittsburgh Hlth Care Syst, Pittsburgh, PA USA
[2] RAND Corp, Pittsburgh, PA USA
[3] Univ Massachusetts, Dept Sociol, Boston, MA 02125 USA
[4] Harvard Med Sch, Dept Psychiat, Boston, MA 02115 USA
[5] Edith Nourse Rogers Vet Hosp, Bedford, MA USA
[6] VA Salt Lake City Hlth Care Syst, Salt Lake City, UT USA
[7] Univ Utah, Med Sch, Salt Lake City, UT 84112 USA
[8] Univ Massachusetts, Med Ctr, Dept Psychiat, Amherst, MA 01003 USA