Disorders, 4th Edition (DSM-IV). All subjects had a history of using heroin multiple times per day, every day for at least one year. The 167 control subjects were recruited at the Rockefeller University Hospital. Each of the following was used as an exclusion criterion from this category: a) At least one instance of drinking to intoxication, or any illicit drug use, in the previous 30 days. b) A past history of alcohol drinking to intoxication, or illicit drug use, more than twice a week, for more than six consecutive months. c) Cannabis use for more than 12 days in the prior 30 days or past use for more than twice a week for more than 4 years. All subjects completed a family history questionnaire and were self-identified as AA for three generations. Participants were excluded from the study if they had a relative in the study, or had a mixed ancestry. The Institutional Review Boards of Rockefeller University, VA NY and Cornell University approved the study. Rockefeller University IRB also reviews the Adeslon Clinic, Las Vegas.. All subjects signed informed consent for genetic studies.
