[1] COLUMBIA UNIV, COLL PHYS & SURG, SCH PUBL HLTH, NEW YORK, NY 10032 USA
[2] NEW YORK STATE PSYCHIAT INST & HOSP, DEPT EPIDEMIOL SUBST ABUSE, NEW YORK, NY 10032 USA
[3] COLUMBIA UNIV, DEPT CHILD PSYCHIAT, NEW YORK, NY 10032 USA
[4] UNIV PUERTO RICO, INST BEHAV SCI, SAN JUAN, PR 00936 USA
[5] EMORY UNIV, DEPT PSYCHOL, ATLANTA, GA 30322 USA
[6] UNIV CHICAGO, DEPT PSYCHOL, CHICAGO, IL 60637 USA
[7] NIMH, DIV EPIDEMIOL & SERV RES, BETHESDA, MD 20857 USA
[8] YALE UNIV, SCH MED, YALE CHILD STUDY CTR, NEW HAVEN, CT 06520 USA