Drug and alcohol use behaviors were measured primarily using the Texas Christian University (TCU) drug history form (Simpson & Chatham, 1995). This questionnaire has been tested in men and women with histories of drug addiction, prostitution, and homelessness. It is used to record lifetime and the past 6-month use of 16 drugs, including cocaine, heroin, and methamphetamine, and elicit information about the current frequency of noninjection and injection drug use. Additional items were used to assess the quantity of alcohol consumed in the past 6 months and attendance at a self-help program in the last 6 months.