[1] Univ Vermont, Substance Abuse Treatment Ctr, Burlington, VT 05401 USA
[2] Univ Vermont, Subst Abuse Treatment Ctr, Burlington, VT 05401 USA
[3] Univ Vermont, Dept Psychol, Burlington, VT 05401 USA
[4] Univ Vermont, Dept Psychiat, Burlington, VT 05401 USA
[5] Univ Vermont, Dept Biostat, Burlington, VT 05401 USA