Self-report of illicit benzodiazepine use on the Addiction Severity Index predicts treatment outcome

The relationship between pre-treatment illicit benzodiazepine use (days of use in the last 30) assessed on the Addiction Severity Index (ASI) and treatment outcome was investigated by retrospective analysis of data from two controlled clinical trials in 361 methadone maintained cocaine/opiate users randomly assigned to 12-week voucher- or prize-based contingency management (CM) or control interventions. Based on screening ASI, participants were identified as non-users (BZD-N; 0 days of use) or users (BZD-U; >0 days of use). Outcome measures were: urine drug screens (thrice weekly); quality of life and self-reported HIV-risk behaviors (every 2 weeks); and current DSM-IV diagnosis of cocaine and heroin dependence (study exit). In the CM group, BZD-U had significantly worse outcomes on in-treatment cocaine use, quality-of-life scores, needle-sharing behaviors, and current heroin dependence diagnoses at study exit compared to BZD-N. In the control group, BZD-U had significantly higher in-treatment cocaine use but did not differ from BZD-N on psychosocial measures. Thus, in a sample of non-dependent BZD users, self-reported illicit BZD use on the ASI, even at low levels, predicted worse outcome on cocaine use and blunted response to CM.