The Addiction Severity Index (ASI)(McLellan et al, 1980) was administered and urine analyses were performed for multiple drugs of abuse on all subjects. Former severe heroin addicts (N = 194) were long-term heroin addicts who met Federal guidelines for methadone maintenance treatment (one year or more of daily multiple injections of heroin or other opiates).(Rettig and Yarmolinsky, 1995) Subjects in the control group (N = 136) had 1) no illicit drug use for more than 6 months (except cannabis), 2) no excessive use of cannabis (three or more times per week for more than four years), 3) no previous history of alcohol drinking to intoxication (three or more times per week for six months or more), and 4) no alcohol intoxication or illicit drug use (except cannabis) in the last 30 days.
