Heroin addiction cases were drawn from the Urban Health Study (UHS) of street-recruited people who reported past 30-day injection of an illicit drug (verified by signs of venipuncture) from the San Francisco Bay area between 1986 and 2005 (Kral et al., 2001, Kral et al., 2003). The current study focused on European Americans and African Americans who met the Office of National Drug Control Policy definition of heroin abuse, having injected 10+ times in the past 30 days (Morral et al., 2000, Rhodes et al., 2000). This level of heroin abuse is highly correlated with clinical dependence levels on the Severity of Dependence Scale (Gossop et al., 1992, Strang et al., 1999) and with DSM-IV heroin abuse/dependence (American Psychiatric Association, 1994) based on our analyses of the National Survey on Drug Use and Health data (Hancock et al., in press). These UHS participants, henceforth referred to as heroin addiction cases, reported abusing heroin an average of 80.9 times in the past 30 days and thus were very likely dependent on heroin.
