1. Department of Psychiatry; New York State Psychiatric Institute/Columbia University; New York New York
2. Division of Epidemiology, Services, and Prevention Research; National Institute on Drug Abuse; Bethesda Maryland
3. Grupo de Investigacion en conductas adictivas; Department of Psychology; University of Oviedo; Oviedo Spain
4. Department of Epidemiology; Mailman School of Public Health; Columbia University; New York New York