The National Drug Abuse Treatment Clinical Trials Network (CTN) includes 13 nodes (research centers) allied with substance abuse treatment providers in 39 states across the United States, the District of Columbia, and Puerto Rico (Tai et al., 2011). For this study, analyses were performed on data from a large, multisite CTN study that evaluated two buprenorphine/naloxone taper schedules for opioid detoxification in 11 outpatient, community-based treatment programs (Ling et al., 2009). Eligible participants were at least 15 years of age and seeking treatment for opioid dependence at one of the participating treatment programs in 10 U.S. cities (Colorado, Connecticut, New York, North Carolina, Oregon, Virginia, and Washington). Recruitment methods included word of mouth, radio announcements, newspaper advertisements, and referrals from local opioid treatment and outreach programs, alcohol and drug abuse clinics, primary care providers, local mental health centers, crisis clinics, and hospital emergency rooms. The sample included 920 opioid-dependent adults from the intake assessment. Opioid-dependent adults who did not meet eligibility criteria were also included in the analysis, which both enabled us to ascertain whether substance use status differed by
